Why is "Writing a science lesson — explaining how CRISPR, cloning or IVF works instead of arguing the ethics" a common mistake in Science, medicine and ethics?

Why it happens: Students who have studied some biology want to show their knowledge, and assume technical detail will impress, when the question is actually about values. How to avoid it: NAME the advance but never explain the mechanism. Cambridge's focus is the ethical and social dimension, not technical depth. Spend your words on whether it is right, for whom and at what cost — if a sentence is teaching biology, delete it. Source: 8021 syllabus (Topic 2) — focus is the ethical and social dimensions of science, not technical knowledge

Why is "Using vague, unnamed examples ('scientists can now edit genes', 'science has gone too far')" a common mistake in Science, medicine and ethics?

Why it happens: Students know the general idea but have not prepared specific, dated examples, so they gesture at evidence rather than providing it. How to avoid it: Replace every vague reference with a NAMED, dated example — He Jiankui (2018), Dolly (1997), Louise Brown (1978), thalidomide, three-parent IVF (2015). Prepare an examples bank with two to three per sub-theme. Vague references earn nothing under AO1; specific ones are the foundation of every higher band. Source: 8021 Examiner Reports — Paper 1: 'unsupported generalisation' is a recurring weakness

Why is "Describing or narrating a case instead of ARGUING in response to the question" a common mistake in Science, medicine and ethics?

Why it happens: Cases like He Jiankui or Dolly are dramatic, so students retell the story rather than using it to test the question's claim. How to avoid it: After every example, ask 'what does this PROVE about the ethics in the question?'. Use the case to support a judgement, not to inform. Description sits in Band 2; analysis that advances an argument reaches Band 4-5. Source: 8021 Examiner Reports — 'largely descriptive responses cannot access the higher bands'

Why is "Omitting the counterargument and writing a one-sided 'science is dangerous' (or 'science is wonderful') essay" a common mistake in Science, medicine and ethics?

Why it happens: Students have a strong gut feeling about science and argue only their own side, fearing that conceding anything weakens their case. How to avoid it: Treat a counterargument paragraph as compulsory: state the opposing view at its strongest (e.g. gene editing could cure terrible diseases), then refute or qualify it (e.g. using the therapy/enhancement distinction). The band descriptors require counterarguments to be 'acknowledged AND addressed' for Band 4-5 — omitting it caps your mark. Source: 8021 Paper 1 band descriptors — Band 5 requires counterarguments acknowledged and addressed

Why is "Ending with 'science can be a force for good but can also be misused' instead of a real judgement" a common mistake in Science, medicine and ethics?

Why it happens: Fear of 'getting it wrong' on a contested ethical issue makes students retreat into a balanced-sounding cliche rather than committing. How to avoid it: Set a criterion earlier (e.g. 'is the benefit proportionate to the harm, and is consent genuine?'), then commit to a verdict with a 'because' (e.g. 'heal, but do not enhance, because...'). Cambridge treats such fence-sitting as an evasion of AO2 and AO3. Source: 8021 Paper 1 guidance — 'a clear, supported conclusion is reached' is required for the top band

Why is "Using an emotive, alarmist or 'playing God' tone without evidence ('this is terrifying and must be stopped')" a common mistake in Science, medicine and ethics?

Why it happens: Science ethics provokes strong feelings, and students slip into the dramatic, fearful style of headlines and social media instead of reasoned argument. How to avoid it: Maintain a formal, analytical register and support claims with named examples and clear reasoning. Note that 'unnatural' is not the same as 'unethical' (IVF proves this). Precise vocabulary (consent, proportionate, irreversible, precautionary principle) and calm reasoning score; ranting does not. AO3 is 45% of Paper 1. Source: 8021 Paper 1 band descriptors (AO3) — register and accuracy of written English

Cambridge International A Levels English General Paper (8021)

Science, medicine and ethics

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Detailed Study Notes

Detailed notes on Science, Environment and Technology for Cambridge International A Levels English General Paper, covering key concepts, explanations, examples, and exam-focused revision points.

Science, Medicine and Ethics: Building A*-Grade Essay Arguments — Cambridge AS Level English General Paper 8021

This subtopic builds the knowledge AND the argument skills you need for Paper 1 essays on the ethics of scientific and medical advances — gene editing and 'designer babies', cloning, stem-cell research, IVF, animal testing, drug trials and AI in medicine. The single rule that decides your grade in 8021: you are marked on HOW you USE examples to argue, not on how much science you know. The exam wants the ETHICAL and SOCIAL debate, not a biology lesson. Vague references ('scientists can now edit genes') earn nothing; named examples (He Jiankui's gene-edited babies in China in 2018, Dolly the cloned sheep in 1997) earn marks.

At a glance

Science, medicine and ethics sits inside Topic 2 (Science, Technology and Environment) and produces a Paper 1 essay question on the ethics of a scientific or medical advance almost every series.
The EXAM FOCUS is the ETHICAL and SOCIAL dimensions of science — NOT technical depth. You do not need to explain how CRISPR works; you need to argue whether using it is right.
8021 is SKILLS-based: marks reward argument, a RANGE of SPECIFIC examples, a counterargument that is answered, and a committed, supported conclusion — not memorised facts.
The recurring axis: scientific POSSIBILITY versus ethical ACCEPTABILITY — just because we CAN do something does not mean we SHOULD.
Named examples that score: He Jiankui's gene-edited babies (China, 2018); Dolly the cloned sheep (1997); the first IVF baby Louise Brown (1978); the rapid mRNA COVID-19 vaccines (2020); the thalidomide drug-testing scandal; the UK legalising 'three-parent' mitochondrial donation (2015); the Henrietta Lacks / HeLa cells consent controversy.
Range matters: contrast High-Income contexts (UK fertility law, US biotech) with the global picture — who can afford these treatments, and who pays the ethical price (LIC/MIC drug trials, unequal access).
A balanced essay that names the strongest counterargument and then ANSWERS it is the gateway to Band 4-5; omitting counterargument caps you below the top.
Your conclusion must JUDGE against a criterion (e.g. 'is the benefit proportionate to the harm and is consent genuine?') — not summarise or sit on the fence.

What you’ll learn

Mapped to the Cambridge International A Level 8021 syllabus (2025-2027).

Build a bank of specific, contrasting international examples on genetic engineering, cloning, reproductive technology, animal testing and drug trials that you can deploy quickly in any Paper 1 essay on the ethics of science (AO1).
Construct balanced arguments that weigh scientific benefit against ethical risk, applying recurring frameworks such as the possibility-versus-acceptability distinction and the precautionary principle (AO1 + AO2).
Apply the command words 'To what extent', 'How far do you agree', 'Discuss' and 'Assess the ethics of' to scientific propositions, recognising that each requires a reasoned judgement of degree, not a yes/no answer.
Write a counterargument paragraph on a contested advance (gene editing, animal testing) that states the opposing view at its strongest and then refutes or qualifies it — the habit that unlocks the top bands (AO2 + AO3).
Reach a committed, criterion-based conclusion on a science-ethics question rather than retreating into 'science is good but can be misused' (AO2 + AO3).
Sustain a formal, analytical register and precise, varied vocabulary across a 600-700 word essay, resisting the temptation to either lecture on the science or write emotively (AO3, the dominant objective in Paper 1).

The rule that decides your grade — and the science-essay trap

Science-ethics essays appear in Paper 1 every year. But you are marked on argument, not on scientific knowledge — and the biggest trap is writing a science lesson instead of an ethical argument.

Science, medicine and ethics sits inside Topic 2: Science, Technology and Environment, one of the three broad areas Paper 1 essays are drawn from. A question on the ethics of a scientific or medical advance appears in essentially every exam series — on gene editing, cloning, reproductive technology, animal testing or healthcare priorities.

But here is the rule that decides your grade in 8021: you are assessed on HOW you use knowledge to argue, not on the knowledge itself. And in science essays this produces a specific, very common trap.

The science-essay trap: writing a biology lesson instead of an ethical argument. When a question asks about gene editing, weaker students explain how CRISPR cuts DNA, or how cloning copies a cell. This earns almost nothing. The Cambridge focus is explicitly the ethical and social dimensions of science — technical depth is not required and not rewarded. The examiner wants to know whether you think the advance is right, for whom, and at what cost — and whether you can argue it.

Two practical consequences:

Specific beats vague, every time. 'Scientists can now edit human genes' earns nothing. 'In 2018 the Chinese scientist He Jiankui announced he had created the world's first gene-edited babies, was widely condemned by the scientific community and later imprisoned' earns marks because it is precise, named and accurate.
Argument beats description. Describing what CRISPR does is description. Deciding whether editing human embryos is ever justified, weighing both sides and reaching a verdict, is argument — and argument is what the band descriptors reward.

Science-ethics questions appear in Paper 1 (Topic 2) essentially every series — prepare them.
8021 is skills-based: marks come from argument, specific examples, counterargument and judgement.
The focus is ETHICAL and SOCIAL, not technical — do NOT explain how the science works.
Replace every vague reference with a named, accurate example (He Jiankui 2018, Dolly 1997).
Move up the ladder: science fact -> specific example -> explained -> ethically judged.

Can versus should — possibility, acceptability and the precautionary principle

The master framework for every science-ethics essay: scientific possibility is not the same as ethical acceptability. Learn to map an advance onto that distinction.

Almost every science-ethics essay turns on one distinction: just because we CAN do something does not mean we SHOULD. Scientific possibility is a question of capability; ethical acceptability is a question of values. The strongest essays separate the two and argue about the gap between them.

Three ethical lenses to apply (you do not need the technical theory — just the everyday version):

Consequences (outcomes): Does the benefit outweigh the harm? mRNA COVID-19 vaccines, developed at unprecedented speed in 2020, saved very many lives — a strong consequence-based case for fast, ambitious science.
Rights and consent: Did those affected agree? The Henrietta Lacks case — whose cells (the 'HeLa' line) were taken without consent in the 1950s and became one of the most important tools in medical research — shows how a hugely beneficial outcome can rest on a serious violation of a person's rights.
Limits and 'playing God': Are there lines science should not cross, regardless of benefit? Critics of human gene editing and cloning often appeal to this, especially around altering future generations who cannot consent.

The precautionary principle. A key term to deploy: where an action's consequences are uncertain but potentially severe and irreversible, we should err on the side of caution. Editing the genes of an embryo changes every future descendant; the precautionary principle warns against doing the irreversible while the long-term effects are unknown — exactly the objection levelled at He Jiankui's 2018 experiment.

How to argue it. Take an advance, place it on the possibility-acceptability map, then judge against a clear criterion — usually some version of 'is the benefit proportionate to the harm, and is consent genuine and informed?'

Master distinction: scientific possibility (can) is not ethical acceptability (should).
Three lenses: consequences (benefit vs harm), rights/consent, and limits ('playing God').
The precautionary principle: avoid the irreversible while long-term effects are unknown.
Consent example: Henrietta Lacks / HeLa cells — great benefit, serious rights violation.
Judge against a criterion: is the benefit proportionate to the harm, and is consent genuine?

Genetic engineering, gene editing and 'designer babies'

The richest source of science-ethics questions. Separate curing disease from enhancement, and build a benefits-versus-risks balance sheet.

Genetic engineering is the single most examined science-ethics theme, usually framed as: do the benefits of genetic engineering outweigh the ethical risks?

The crucial distinction: therapy versus enhancement.

Therapy — using gene editing to prevent or cure serious disease (for example, correcting a faulty gene that causes a hereditary illness). Far easier to defend.
Enhancement — editing for non-medical 'improvements' (intelligence, height, appearance): the 'designer baby' debate. Far harder to defend, because it raises fairness, identity and eugenics concerns.

Named examples to deploy:

He Jiankui's gene-edited babies (China, 2018) — the scientist announced he had edited the embryos of twin girls to resist HIV. The work was widely condemned as reckless and unethical, and he was later imprisoned. The headline case of crossing an ethical line.
CRISPR — the gene-editing technology that made such interventions cheaper and more accessible (you can NAME it without explaining the biology). Its power is precisely what makes the ethics urgent.
Three-parent IVF / mitochondrial donation (UK, 2015) — the UK became the first country to legalise a technique using DNA from three people to prevent mothers passing on serious mitochondrial diseases. A contrasting case of careful regulation: a genuine medical benefit, debated openly, approved under strict rules.

The benefits. Eliminating inherited diseases; reducing suffering; potentially feeding more people through engineered crops.

The ethical risks. Editing embryos changes future generations who cannot consent; unknown long-term effects (the precautionary principle); a slide from curing disease to designing children; and a serious equity problem — if only the wealthy can afford enhancements, genetic advantage could entrench inequality, a modern echo of eugenics.

How to argue it. Build a balance sheet, but make the therapy/enhancement line do the work: many essays conclude that gene editing to cure serious disease is defensible under strict regulation, while enhancement is not — a nuanced, criterion-based judgement rather than a blanket 'for' or 'against'.

Separate therapy (curing disease — defensible) from enhancement ('designer babies' — contested).
He Jiankui's gene-edited babies (China, 2018): condemned, jailed — the line-crossing case.
Three-parent IVF / mitochondrial donation (UK, 2015): a regulated, defensible medical use.
Name CRISPR as the enabling technology — do NOT explain how it works.
Risks: no consent of future generations, unknown effects, eugenics, unequal access.

Cloning, stem cells and reproductive technology

Three linked debates about creating and shaping life. Note how the same advance can move from 'shocking' to 'routine' as society adapts.

These three themes ask how far science should go in creating, copying and shaping human life.

Cloning. Dolly the sheep (1997) was the first mammal cloned from an adult cell — a landmark that triggered worldwide debate about whether humans might be cloned next. Most countries banned reproductive human cloning. The ethics: cloning could in principle help with disease research, but reproductive cloning raises concerns about identity, the welfare of a cloned individual, and treating a person as a manufactured copy rather than a unique being.

Stem-cell research. Stem cells can develop into many types of tissue, offering hope for treating conditions from spinal injury to Parkinson's. The ethical flashpoint has been embryonic stem cells, since obtaining them has historically involved destroying an early embryo — pitting the potential to cure serious disease against beliefs about the moral status of the embryo. A clean example of the benefit-versus-principle clash.

Reproductive technology. Louise Brown (1978), the world's first 'test-tube baby' born through IVF, was greeted at the time with fear about 'unnatural' birth — yet IVF is now a mainstream, widely accepted treatment that has helped millions of families. This is a powerful exam point: society's ethical comfort can shift dramatically as a technology proves safe and beneficial. The same arc may, or may not, apply to today's contested advances.

The recurring argument. Each theme weighs the relief of suffering and the advance of knowledge against deep concerns about the status of human life, consent and 'naturalness'. The maturest line notes that 'unnatural' is not the same as 'unethical' (IVF proves this), while insisting that genuine ethical concerns — consent, the moral status of the embryo, the welfare of any resulting person — still need answering case by case.

The exam value here is that you can argue both that science should push forward to relieve suffering and that some lines (reproductive human cloning, destroying embryos casually) should be drawn — reaching a discriminating judgement rather than a blanket one.

Dolly the sheep (1997): first cloned mammal; most countries banned reproductive human cloning.
Stem cells: huge medical promise, but embryonic stem cells clash with views on the embryo's status.
Louise Brown (1978): first IVF baby — feared at first, now mainstream and widely accepted.
Key insight: ethical comfort can shift as a technology proves safe (IVF's journey).
'Unnatural' is not the same as 'unethical' — but consent and welfare concerns still need answering.

Animal testing, drug trials, AI in medicine — and who controls science

The themes that broaden a science essay into society: how we test treatments, the ethics of AI diagnosis, and who should fund and govern research.

These themes let you widen a science-ethics essay from the laboratory to society — fresh, high-scoring material because it engages funding, justice and accountability.

Animal testing (vivisection). Testing on animals has driven major medical advances (vaccines, surgical techniques, many drugs), yet causes animal suffering. The classic axis: human benefit versus animal welfare. The strongest answers acknowledge that much modern medicine depended on animal research, then weigh this against the welfare cost and the rise of alternatives (cell cultures, computer modelling), arguing for strict regulation and the '3Rs' (replace, reduce, refine) rather than a simple ban or a free hand.

Drug testing and trials. New medicines must be tested on people, which carries risk. The thalidomide scandal — a drug prescribed to pregnant women that caused severe birth defects before it was withdrawn — is the landmark example of why rigorous trials and regulation exist. A second, global-justice angle: pharmaceutical trials are sometimes run in poorer countries where participants may be more vulnerable and consent harder to ensure — a powerful point about who bears the RISKS of medical progress while wealthier nations enjoy the BENEFITS.

AI in medicine. Artificial intelligence can now help diagnose disease and read scans, sometimes faster or more accurately than humans. The ethics: who is responsible if an AI gets a diagnosis wrong? Does reliance on algorithms erode the human relationship between doctor and patient? And whose data trained the system, and did patients consent to its use? A very contemporary, high-credit theme.

Who should fund and control science? Behind every advance lies a question of power: should research be driven by governments (accountable but slow), universities, or private companies (fast but profit-driven)? Profit motives can speed up cures but also push prices beyond the reach of the poor, raising the access problem — a life-saving treatment that only the rich can afford is a scientific success but an ethical failure.

The exam pay-off. Each of these themes lets you take a clear position, name precise examples (thalidomide, AI diagnosis, the 3Rs), bring in global justice and access, and reach a judgement — the exact recipe for the top bands.

Animal testing: human benefit vs animal welfare; argue strict regulation and the 3Rs, not a blanket verdict.
Thalidomide scandal: the landmark case for rigorous, regulated drug trials.
Global justice: trials in poorer countries raise who bears the RISK vs who gets the BENEFIT.
AI in medicine: responsibility for errors, the doctor-patient relationship, and data consent.
Who funds/controls science shapes access — a cure only the rich can afford is an ethical failure.

Quick recap

Science, medicine and ethics is a Topic 2 staple in Paper 1 — a question on the ethics of an advance appears almost every series.
8021 is skills-based: you are marked on argument, range of SPECIFIC examples, counterargument and a supported judgement — NOT on scientific knowledge.
Avoid the science-lesson trap: never explain how CRISPR or cloning works; argue whether it is RIGHT.
Master framework: scientific possibility (can) is not ethical acceptability (should); use consequences, consent/rights and limits, plus the precautionary principle.
Gene editing: separate therapy (defensible) from enhancement/'designer babies' (contested); He Jiankui 2018 (line-crossing) vs three-parent IVF UK 2015 (regulated).
Cloning (Dolly 1997), stem cells and reproduction (Louise Brown 1978) show ethical comfort can shift as a technology proves safe — but consent and welfare still matter.
Animal testing (3Rs), drug trials (thalidomide; trials in poorer countries), AI in medicine and access/funding broaden the essay into justice.
Always: name your examples, write a counterargument and answer it, and end with a committed, criterion-based judgement.

Memorise this

Verbatim phrases and definitions Cambridge mark schemes credit.

He Jiankui's gene-edited babies (China, 2018) — widely condemned, later imprisoned; the line-crossing case.
CRISPR — the gene-editing technology to NAME (without explaining the biology).
Dolly the sheep (1997) — first mammal cloned from an adult cell; triggered human-cloning bans.
Louise Brown (1978) — world's first IVF baby; feared then, mainstream now.
mRNA COVID-19 vaccines (2020) — developed at unprecedented speed; the strong consequences-based case.
Three-parent IVF / mitochondrial donation (UK, 2015) — first country to legalise; regulated medical use.
The thalidomide scandal — birth defects from an inadequately tested drug; the case for rigorous trials.
Henrietta Lacks / HeLa cells — hugely beneficial research built on cells taken without consent.
The therapy-versus-enhancement distinction — curing disease vs 'designer babies'.
The precautionary principle and the 3Rs (replace, reduce, refine) for animal testing.

How it’s examined

This theme is examined through Paper 1 (the Essay, 30 marks), within Topic 2 (Science, Technology and Environment). You choose ONE of ten questions and write an argued essay of roughly 600-700 words. Typical science-ethics stems are degree, agreement, discussion and assessment questions — 'To what extent are the benefits of genetic engineering worth the ethical risks?', 'How far do you agree that scientists should be free to pursue knowledge without ethical restrictions?', 'Discuss the view that there should be no limits on medical research.', 'Assess the ethics of animal testing.' All three Assessment Objectives apply, with AO3 (communication) the largest at 45%, then AO2 (analysis and evaluation) at 35% and AO1 (selection and application) at 20%. To reach Band 4-5 (19-30) you must sustain a coherent argument, use a RANGE of relevant, SPECIFIC examples (named advances, dated, from contrasting contexts), acknowledge AND address a counterargument, write in accurate, varied, formal English, and reach a clear, supported conclusion. Crucially, keep the focus on ETHICS, not on explaining the science. Note that Paper 2 (Comprehension) may use a science or medical text on its insert, but there ALL content comes from the unseen passage — you must NOT import your own scientific knowledge in Paper 2; your job there is to read, interpret, summarise and analyse the given text. Keep the two orientations separate: argue from knowledge in Paper 1; work only from the text in Paper 2.

Sources: Cambridge International AS Level English General Paper 8021 syllabus (for examination in 2025, 2026 and 2027); 8021 Paper 1 (Essay) and Paper 2 (Comprehension) specimen papers and mark schemes; 8021 / 8004 Examiner Reports — Paper 1 essay band descriptors and common candidate weaknesses. Last reviewed 2026-06-22.

Take this whole topic with you

Step-by-step worked examples — Science, medicine and ethics

Step-by-step solutions to past-paper-style questions on science, medicine and ethics, written exactly the way a tutor would explain them at the board.

1Getting started: building a specific examples bank for science and ethics
Getting started• Paper 1, examples, technique, AO1
Question
Question theme: the ethics of scientific and medical advances. Show how to turn vague references ('scientists can now edit genes', 'science can be misused') into named, marks-earning examples ready for a Paper 1 essay.
Step-by-step solution
1. Step 1
  See why vague references score nothing. In 8021, AO1 rewards 'relevant, specific examples'. 'Scientists can now edit human genes' is generic and unverifiable, so it earns no credit. The fix is to NAME the example AND date it.
2. Step 2
  Map the sub-themes you might be asked about. For this topic: (a) gene editing / 'designer babies', (b) cloning, (c) stem cells, (d) reproductive technology / IVF, (e) animal testing and drug trials, (f) AI in medicine and access/funding. Aim for two to three named examples per sub-theme.
3. Step 3
  Attach a precise, accurate example to each, with a one-line ethical point. e.g. Gene editing -> He Jiankui's gene-edited babies (China, 2018; condemned, jailed — no consent). Cloning -> Dolly the sheep (1997 — triggered human-cloning bans). Reproduction -> Louise Brown (1978 — feared, now mainstream). Drug trials -> the thalidomide scandal (why rigorous testing exists). Consent -> Henrietta Lacks / HeLa cells.
4. Step 4
  Spread examples across contexts so you can show RANGE — the regulated UK approach (three-parent IVF legalised 2015), the global-justice angle (drug trials in poorer countries; unequal access to costly treatments), and the speed-of-progress case (mRNA COVID-19 vaccines, 2020). Range is explicitly rewarded in the band descriptors.
5. Step 5
  Pressure-test each example for accuracy and resist the science-lesson trap. Commit only to facts you are confident of (Dolly was 1997; Louise Brown was 1978; He Jiankui was 2018). Hedge anything uncertain ('over a million IVF births') rather than inventing a precise statistic. And note: you NAME CRISPR, you do not EXPLAIN how it cuts DNA.
Answer
Replace every 'scientists can now...' with a NAMED, dated example carrying a one-line ethical point; prepare two to three per sub-theme, spread across contexts, and verify accuracy. A ready examples bank lets you build an ethical argument fast in the exam.
Examiner tip
AO1 (20% of Paper 1) credits the SELECTION and APPLICATION of specific, relevant examples. Examiner reports repeatedly note that vague, unsupported generalisation is the most common reason able candidates underperform. Named, accurate, varied examples — used to argue ethics, not to describe science — are the foundation every band above 2 is built on.
2Getting started: decoding a science-ethics question and avoiding the science lesson
Getting started• Paper 1, command words, question choice, technique
Question
You have two science options: (i) 'To what extent are the benefits of genetic engineering worth the ethical risks?' and (ii) 'Assess the ethics of animal testing.' How do you decode each, and how do you avoid drifting into explaining the science?
Step-by-step solution
1. Step 1
  Underline the command word. 'To what extent' and 'Assess' both require a BALANCED, argued response that reaches a judgement of degree — not a yes/no answer and not a description. Both demand a counterargument.
2. Step 2
  Identify the ETHICAL focus, not the scientific one. Question (i) is about whether the BENEFITS (curing disease) justify the RISKS (consent, eugenics, access) — not about how gene editing works. Question (ii) is about whether human benefit justifies animal suffering. The word 'ethics'/'worth' is your signal to argue values, not mechanisms.
3. Step 3
  Test your examples bank against each. For (i): He Jiankui (2018), three-parent IVF (UK 2015), the therapy/enhancement distinction, access inequality. For (ii): thalidomide, the 3Rs, medical advances built on animal research, modern alternatives. Choose the question for which you have the most specific, varied examples.
4. Step 4
  Set a one-line 'no science lesson' rule for yourself. Before writing, tell yourself: 'I will NAME the advance but never explain the biology.' If a sentence is teaching how CRISPR or cloning works, delete it — that earns nothing and burns words you need for argument.
5. Step 5
  Sketch a one-line verdict, then commit. e.g. for (i): 'editing to cure serious disease is defensible under strict rules; enhancement is not.' Cambridge advises reading all ten questions and choosing the one you can ARGUE most fully. Pick the question where your conclusion is already clear, then do not switch halfway.
Answer
Decode the command word (both need a balanced, judged argument), read the question as an ETHICAL one, match it to your examples bank, set a 'no science lesson' rule, and commit to the question you can argue most fully.
Examiner tip
Examiner reports note that science essays are frequently weakened by candidates explaining the science instead of arguing the ethics, and by poor question choice (picking the topic they like over the one they can ARGUE). Spending five minutes decoding and choosing protects all three AOs and avoids the most common science-essay pitfall.
3Building confidence: structuring a 'To what extent' essay on ethical limits to science
Building confidence• Paper 1, structure, To what extent, AO3
Question
Question: 'To what extent should science be subject to ethical limits?' Build a structure that guarantees argument, range and a judgement.
Step-by-step solution
1. Step 1
  Write an introduction that states a position, not the question. Define scope (ethical limits = rules on what research may be done, e.g. on embryos, consent, animals) and the master distinction (possibility vs acceptability). State your line — e.g. 'science should be free to pursue knowledge but not free of all limits' — and signal a counterview exists. Avoid 'In this essay I will discuss...'.
2. Step 2
  Body paragraph 1 — first point FOR limits, with a specific example. e.g. some advances cause irreversible harm without consent: He Jiankui's 2018 gene-edited babies altered children who could never agree, and was condemned worldwide. End by linking back to 'how far should limits go'.
3. Step 3
  Body paragraph 2 — a point about the COST of limits, from a different context to show range. e.g. excessive restriction can slow life-saving progress: the mRNA COVID-19 vaccines (2020) showed how fast, ambitious science saves lives, and over-caution can itself cause harm.
4. Step 4
  Counterargument paragraph — state the opposing view at its strongest, then answer it. e.g. 'It is argued that knowledge should be entirely free and that ethics merely holds science back; yet the thalidomide scandal shows that the absence of rules costs lives, so limits protect rather than obstruct progress.'
5. Step 5
  Conclusion that JUDGES with a criterion. e.g. 'Measured by whether harm is proportionate and consent genuine, science should be free to pursue most knowledge but firmly limited where it risks irreversible harm to those who cannot consent — so limits should be real but targeted, not blanket.' Commit; do not summarise.
Answer
Intro (position + the possibility/acceptability distinction) -> point FOR limits with named example -> point on the COST of limits from another context -> counterargument answered -> criterion-based judgement. The judgement and the range of examples earn the top band, not the amount of science.
Examiner tip
Paper 1 is 45% AO3 (structured, cohesive, accurate writing), 35% AO2 and 20% AO1. A disciplined five-part structure earns AO3 directly and creates the slots where AO2 (analysis, counterargument, judgement) is demonstrated. Band 5 requires the argument to be 'coherent and sustained throughout' — here, sustained around the single thread of proportionate, consent-based limits.
4Building confidence: writing the counterargument paragraph on gene editing
Building confidence• Paper 1, counterargument, AO2, technique
Question
Essay claim: 'Genetic engineering of humans should be banned.' Show how to write a counterargument paragraph that lifts the essay into Band 4-5 rather than weakening your case.
Step-by-step solution
1. Step 1
  Understand why counterargument is non-negotiable. The band descriptors require counterarguments to be 'acknowledged AND addressed' for Band 4-5. Omitting the opposing view caps the essay below the top, however fluent it is.
2. Step 2
  State the opposing view at its STRONGEST. Do not build a straw man. e.g. 'It is powerfully argued that a ban is cruel: gene editing could eliminate devastating inherited diseases, and the UK's legalisation of three-parent IVF in 2015 shows that such interventions can prevent real suffering under careful regulation.'
3. Step 3
  Support it briefly with a specific example (three-parent IVF, 2015; the prospect of curing hereditary disease). A concession backed by a real example shows confidence and fairness — and is far more persuasive than ignoring the other side.
4. Step 4
  Then REFUTE or QUALIFY it — using the therapy/enhancement distinction. e.g. 'However, this defends therapy, not a free hand: a blanket permission opens the door to enhancement and 'designer babies', as He Jiankui's reckless 2018 experiment showed. The answer is therefore not a total ban but strict regulation that permits curing disease while forbidding enhancement.'
5. Step 5
  Link the refutation back to the question. e.g. 'so an outright ban is too blunt: the better response is tight control, which is why I argue against a total ban while insisting on firm ethical limits.' The counterargument now SHARPENS your position rather than undermining it.
Answer
Counterargument = strongest opposing view (gene editing cures disease) + specific support (three-parent IVF) + reasoned qualification (therapy yes, enhancement no) + link back. Done well, it raises your mark and refines your thesis; omitted, it caps you below Band 4-5.
Examiner tip
AO2 (35%) credits 'supported judgements' and evaluation. The band descriptors single out counterargument: it must be acknowledged AND addressed for the upper bands. Using the therapy/enhancement distinction to absorb the opposing case — rather than just rebutting it — demonstrates exactly the balanced, discriminating reasoning examiners reward.
5Stretch: reaching a committed A* conclusion on a science-ethics question
Stretch• Paper 1, conclusion, judgement, A*
Question
Many students end a science essay with 'science can be a force for good but can also be misused'. Show how to turn a balanced science-ethics essay into a genuinely A*-level supported conclusion.
Step-by-step solution
1. Step 1
  Recognise the fence as a fault, not safety. 'Science can be good but can be misused' is the science-essay version of fence-sitting — Cambridge treats such evasion as a failure of AO2 and AO3, because it refuses to answer the command word's 'to what extent' or 'assess'.
2. Step 2
  Set an explicit criterion earlier in the essay so the conclusion can apply it. For science-ethics, a strong criterion is: 'is the benefit proportionate to the harm, and is consent genuine and informed?' This gives the conclusion a yardstick to deliver a verdict.
3. Step 3
  Use a discriminating distinction rather than an all-or-nothing verdict. e.g. separate therapy from enhancement, or curing disease from creating it, or willing adult consent from imposing risk on those who cannot consent. Nuance is not fence-sitting if it leads to a decision.
4. Step 4
  Answer the strongest counter-point in one clause, then decide. e.g. 'Although progress like the rapid COVID-19 vaccines shows the cost of over-caution, this argues for proportionate limits, not for none...'.
5. Step 5
  Write a verdict that COMMITS with a 'because'. e.g. 'Genetic engineering is therefore justified to cure serious disease but not to enhance, because the first relieves proven suffering with consent while the second imposes uncertain, irreversible risk on those who cannot agree.' One position, one reason.
Answer
A* conclusion = explicit criterion (proportionate benefit + genuine consent) + a discriminating distinction (e.g. therapy vs enhancement) + answering the strongest counter-point + a committed 'because' verdict. 'Science can be good or bad' is not a conclusion.
Examiner tip
Examiner reports state the difference between the top two bands is often a 'clear, supported conclusion' that is reached and sustained, not the volume of knowledge. In science essays, a criterion-based, committed verdict (rather than the vague 'force for good / can be misused' ending) is the single most reliable A* habit in Paper 1.
6Stretch: deploying contrasting examples and analysing, not describing the science
Stretch• Paper 1, range, analysis, A*
Question
Show how to use contrasting examples to demonstrate RANGE while ANALYSING the ethics (not describing the science) — e.g. on 'How far do you agree that the benefits of medical research outweigh its ethical costs?'
Step-by-step solution
1. Step 1
  Choose examples from contrasting contexts. Benefit case: the rapid mRNA COVID-19 vaccines (2020) saved very many lives. Cost case: the Henrietta Lacks / HeLa cells controversy, where hugely beneficial research rested on cells taken without consent. Two different angles on the same question.
2. Step 2
  Make the contrast do analytical WORK, not decoration. The point is not 'here are two cases' but 'the benefit and the cost are often separate questions: the COVID vaccines were both beneficial AND consented to, while HeLa was beneficial BUT unconsented — so the real issue is not benefit versus cost but whether benefit is pursued justly'. The contrast PROVES that claim.
3. Step 3
  Avoid the description trap twice over. Do not narrate the history of HeLa cells, and do not explain how mRNA vaccines work. Use each example to TEST the question's claim. Always ask 'what does this example PROVE about the ethics?', not 'what happened?'.
4. Step 4
  Signal the comparison explicitly with discourse markers — 'Whereas the COVID-19 vaccines...', 'By contrast, the HeLa case...', 'This suggests the difference lies not in the benefit but in the consent.' Cohesion and signposting are credited under AO3.
5. Step 5
  Draw a mini-judgement from the contrast before moving on: 'so medical research is justified where benefit is pursued with genuine consent, and condemned where it is not — making consent, not benefit, the decisive test.' Each paragraph ending in a mini-judgement builds towards the conclusion.
Answer
Pair contrasting examples (consented benefit vs unconsented benefit) so the CONTRAST proves a point about the ethics, signpost it clearly, and end with a mini-judgement. Range plus ethical analysis — never narration of the science — is what earns the top band.
Examiner tip
Band 5 requires a 'wide range of relevant examples used effectively to support and develop the argument'. The word 'effectively' is key: examples must be ANALYSED to advance the ethical argument, not listed or narrated. Contrasting cases that isolate a single variable (here, consent) are the most efficient way to demonstrate range AND analytical depth at once.

Model Answers — Science, medicine and ethics

High-scoring sample answers for science, medicine and ethics on the Cambridge IGCSE paper, with examiner-style notes mapping each response to the mark scheme and assessment objectives.

Question 1
8021 Paper 1-style essay question30 marks
[EASY] Write a model INTRODUCTION and a bullet-point PLAN for the essay: 'To what extent are the benefits of genetic engineering worth the ethical risks?' (Paper 1 Essay, 30 marks) — only the introduction and plan are modelled here.
Model answer
Model introduction (~90 words):

Few scientific powers promise as much, or provoke as much unease, as the ability to rewrite the human genome. By "benefits" I mean above all the prevention of inherited disease, and by "ethical risks" the dangers of altering people who cannot consent and of widening inequality. This essay will argue that the benefits are worth the risks only when genetic engineering is used to cure serious disease under strict regulation; once it shifts towards enhancement and "designer babies", the risks decisively outweigh the gains.

Bullet-point plan:

Body 1 (benefit): Curing inherited disease relieves real suffering — the UK's legalisation of three-parent IVF (2015) shows a regulated, defensible medical use. Link: therapy is worth the risk.

Body 2 (risk): Editing embryos changes future generations who cannot consent and may be irreversible — He Jiankui's reckless gene-edited babies (China, 2018) crossed this line and were condemned worldwide.

Body 3 (risk): Enhancement raises eugenics and equity fears — if only the wealthy can afford genetic advantage, inequality is entrenched.

Counterargument: Some argue ALL such research should be banned as 'playing God'; but IVF (once feared, now routine since Louise Brown in 1978) shows revulsion is a weak guide, so a ban is too blunt.

Conclusion: The benefits are worth the risks for therapy under strict rules, but not for enhancement — the line, not the technology, is what matters.
Why this scores
A strong introduction for Band 5: it states a clear, nuanced position, DEFINES the key terms ('benefits', 'ethical risks'), and signals the therapy/enhancement distinction that will structure the argument — without explaining any biology. The plan shows three developed points with NAMED, dated examples from different contexts (three-parent IVF 2015, He Jiankui 2018, Louise Brown 1978), a counterargument to be answered, and a committed conclusion — the exact architecture the band descriptors reward (AO3 structure + AO2 signposting).
Question 2
8021 Paper 1-style essay question30 marks
[EASY] Write one fully-developed BODY PARAGRAPH (Point -> specific Example -> Analysis -> Link) for the essay: 'Assess the ethics of animal testing.' (Paper 1 Essay, 30 marks) — only one body paragraph is modelled here.
Model answer
One powerful argument in favour of animal testing is that much of modern medicine, which now saves and improves countless human lives, was developed through it. (Point) Many vaccines, surgical techniques and life-saving drugs were tested on animals before they could safely be given to people, and the rigorous testing now demanded of new medicines exists precisely because of disasters such as the thalidomide scandal, in which an inadequately tested drug caused severe birth defects. (Example) This suggests that animal testing is not gratuitous cruelty but a stage in protecting human patients from harm: where a treatment cannot yet be safely trialled on people, testing it first on animals can prevent far greater human suffering, which gives it a serious ethical justification. (Analysis) However, this justification is conditional, not absolute: it holds only where the human benefit is real and where suffering is minimised through regulation and the '3Rs' — replace, reduce, refine — rather than where animals are used needlessly or for trivial products. (Analysis) Animal testing is therefore ethically defensible in essential medical research under strict controls, but the strength of that defence depends entirely on the conditions attached — a tension this essay will weigh. (Link)
Why this scores
A model body paragraph: it follows Point -> Example -> Analysis -> Link, uses precise material (the thalidomide scandal; the 3Rs) and crucially ANALYSES rather than describes — it tests the claim ('is it ethical?') and makes the justification conditional rather than blanket. It never explains the biology of how testing works. The closing link advances the overall argument. This is AO1 (specific examples) and AO2 (conditional, evaluative analysis — the seed of a judgement) working together.
Question 3
8021 Paper 1-style essay question30 marks
[MEDIUM] 'To what extent should there be limits on stem-cell and embryo research?' Write a strong introduction, two developed body paragraphs and a counterargument paragraph (about 400 words). (Paper 1 Essay, 30 marks)
Model answer
Stem-cell and embryo research sits at the heart of one of medicine's hardest dilemmas: the conflict between the relief of human suffering and beliefs about the moral status of early human life. By "limits" I mean legal restrictions on what such research may do. This essay argues that limits are necessary, but that they should regulate rather than forbid: research promising to cure serious disease should be permitted under strict conditions, not banned.

The case for allowing this research is its extraordinary medical promise. Stem cells can develop into many kinds of tissue, offering hope for conditions from spinal injury to Parkinson's disease that currently have no cure. To forbid such research outright would be to turn away from treatments that could relieve immense suffering, simply because the science is new and unsettling. History counsels caution about reflexive bans: when Louise Brown, the first IVF baby, was born in 1978, the technique was widely feared as unnatural, yet IVF is now a mainstream treatment that has helped millions of families. Present discomfort is a poor guide to long-term ethics.

Yet this does not mean research should be unlimited. The genuine ethical difficulty is that obtaining embryonic stem cells has historically involved destroying an early embryo, which many regard as possessing moral status. A society that allowed embryos to be created and destroyed casually, or used without clear rules and consent, would have crossed a real ethical line, not merely an emotional one. The lesson of the Henrietta Lacks case — whose cells became invaluable to research after being taken without her consent in the 1950s — is that even hugely beneficial science can rest on a serious wrong. Limits exist precisely to ensure that benefit is pursued justly.

It might be objected that any limits are an unwarranted brake on progress, and that scientists should be free to pursue knowledge wherever it leads, since over-caution itself costs lives by delaying cures. There is real force in this: the rapid development of the mRNA COVID-19 vaccines in 2020 showed how fast, ambitious science can save very many lives, and excessive restriction can be its own kind of harm. However, this argues for proportionate limits, not for none. The thalidomide scandal is a permanent reminder that the absence of rules costs lives too; well-designed regulation does not stop beneficial research but channels it, ensuring that the pursuit of cures does not trample consent or the respect owed to human life.
Why this scores
A clear upper-band part-essay (Band 4-5 trajectory). The introduction defines the key term and states a precise, criterion-led position (regulate, not forbid). Two developed body paragraphs argue BOTH directions with specific, varied material (Louise Brown 1978; the Henrietta Lacks consent case), and the counterargument paragraph states the freedom-of-research objection at its strongest (the mRNA vaccine case) before answering it with thalidomide. The ethics, not the science, is the focus throughout. AO1 (named examples), AO2 (balanced analysis, counterargument addressed) and AO3 (formal register, cohesion) are all evident; a full essay would add a committed conclusion.
Question 4
8021 Paper 1-style essay question30 marks
[MEDIUM] 'How far do you agree that artificial intelligence will improve healthcare?' Write an introduction, two developed body paragraphs and a counterargument paragraph (about 400 words). (Paper 1 Essay, 30 marks)
Model answer
Artificial intelligence is increasingly being used to diagnose disease, read medical scans and manage patient records, and many predict it will transform medicine. By "improve healthcare" I mean making it more accurate, more accessible and more humane. This essay argues that AI is likely to improve healthcare significantly, but only if its ethical risks — responsibility, consent and the human relationship between doctor and patient — are deliberately managed; left unchecked, those same risks could undermine the gains.

The strongest case for AI is its potential to make diagnosis faster and more accurate. AI systems can analyse medical images and detect patterns in data more quickly than overstretched human clinicians, and in some trials have matched or exceeded specialists at spotting particular conditions. In regions with too few doctors, such tools could extend reliable diagnosis to people who currently have little access to specialist care, addressing one of the deepest inequalities in global health. Used well, AI could therefore not only raise quality but widen access.

However, the benefits depend on resolving serious ethical questions. The first is responsibility: if an AI system makes a wrong diagnosis, who is accountable — the doctor, the hospital, or the company that built it? The second is data and consent: these systems are trained on patients' medical records, and patients may never have agreed to their information being used in this way, echoing the wider problem of consent seen in cases such as the Henrietta Lacks controversy. If trust in how data is used breaks down, the technology's promise will be undermined by the suspicion surrounding it.

It might be objected that AI threatens to dehumanise medicine, reducing patients to data points and eroding the relationship of care and trust between doctor and patient that is itself part of healing. This is a serious concern, and a healthcare system run by algorithms alone would indeed be a poorer one. Yet it argues for using AI as a tool that supports clinicians rather than replacing them: if AI handles pattern-spotting and routine analysis, it can free doctors to spend more time on the human aspects of care, not less. The danger lies not in the technology itself but in how it is deployed — which is precisely why ethical management, not blanket optimism or fear, should shape its adoption.
Why this scores
A Band 4-5 part-essay. It establishes a precise, conditional position (AI will improve healthcare IF its risks are managed), then develops it with specific ethical material — diagnostic accuracy and access, responsibility for error, data consent (linked to Henrietta Lacks) — without lapsing into a technical account of how AI works. The counterargument (dehumanisation) is genuinely engaged and then turned into support for the thesis (AI as a tool supporting clinicians), a sophisticated AO2 move. Register is consistently formal (AO3), with strong linking back to 'improve healthcare'.
Question 5
8021 Paper 1-style essay question (A* exemplar)30 marks
[HARD] 'Scientists should be free to pursue knowledge without ethical restrictions.' How far do you agree? (Paper 1 Essay, 30 marks) — full essay of approximately 660 words.
Model answer
The idea that scientists should be free to pursue knowledge without ethical restrictions has a certain nobility: it appeals to the value of curiosity and the long history of discoveries that were once feared and are now indispensable. Yet its absolutism is also its weakness. By "ethical restrictions" I mean limits on what research may be done, to whom, and with whose consent. This essay argues that scientists should indeed be largely free to pursue knowledge, but not without ethical restrictions, because the few but crucial limits that protect human dignity and consent are what make scientific progress trustworthy rather than dangerous.

There is a real case for scientific freedom, because history repeatedly shows that today's taboo becomes tomorrow's routine relief. When Louise Brown, the first "test-tube baby", was born in 1978, IVF was condemned as unnatural meddling; today it is a mainstream treatment that has brought millions of children into the world. Had fear been allowed to forbid the research, that good would have been lost. The rapid development of the mRNA COVID-19 vaccines in 2020 makes the same point with urgency: ambitious, fast-moving science saved very many lives, and excessive caution would itself have cost them. Freedom to pursue knowledge, then, is not a luxury but a source of immense human benefit, and the instinct to restrict the new and unsettling is often mistaken.

However, the claim that there should be NO ethical restrictions cannot survive contact with what unrestricted science actually does to people. In 2018, the Chinese scientist He Jiankui announced he had created the world's first gene-edited babies, altering embryos in ways that would pass to all their descendants. The reaction was near-universal condemnation, and he was later imprisoned — not because the knowledge was uninteresting, but because the children could not consent, the risks were unknown and irreversible, and the work crossed a line that protects future generations. This is exactly what the precautionary principle warns against: where harm could be severe and irreversible, the pursuit of knowledge must yield to caution. A science without restrictions would license precisely such experiments.

The same lesson runs through medicine's history. The thalidomide scandal, in which an inadequately tested drug caused severe birth defects, shows that the absence of ethical rules costs lives directly; the rigorous testing now required exists because freedom without restriction proved disastrous. And the Henrietta Lacks case — whose cells became one of medicine's most valuable tools after being taken without her consent — demonstrates that even hugely beneficial research can rest on a serious violation of a person's rights. In each case the problem was not the knowledge but the absence of limits protecting consent and dignity.

It could be objected that ethical restrictions merely hold science back, that they are imposed by people who do not understand the research, and that progress demands the freedom to follow knowledge wherever it leads. There is partial truth here: clumsy or excessive regulation can delay cures, and over-caution is a genuine harm. But this argues for restrictions that are proportionate and well-designed, not for their abolition. The contrast between He Jiankui's reckless gene editing and the United Kingdom's careful, openly debated legalisation of three-parent IVF in 2015 shows the difference: the first was unrestricted and condemned, the second was regulated and accepted. Restrictions did not stop the beneficial work; they made it trustworthy.

In conclusion, I disagree with the proposition as stated. Scientists should be free to pursue the overwhelming majority of knowledge, and the instinct to ban the unfamiliar is usually wrong; but a science entirely without ethical restrictions would license experiments on those who cannot consent and harms that cannot be undone. The right principle is therefore not freedom without restriction, but freedom within limits that protect consent, dignity and the irreversible — limits that, far from obstructing progress, are what allow society to trust it.
Why this scores
An A* (Band 5, 25-30) essay. It interrogates the absolutism of 'without ethical restrictions' and sustains a single, coherent thesis (largely free, but not without limits) throughout. It deploys a WIDE RANGE of specific, accurate, dated examples used to ANALYSE rather than describe (Louise Brown 1978, mRNA vaccines 2020, He Jiankui 2018, thalidomide, Henrietta Lacks, three-parent IVF 2015), never explaining the underlying science. It explicitly acknowledges AND answers the strongest counterargument (restrictions hold science back) by distinguishing proportionate from excessive limits, and reaches a clear, committed, criterion-based conclusion. Register is formal and varied, structure tightly signposted — satisfying AO3 (45%), AO2 (35%) and AO1 (20%) at the top level.
Question 6
8021 Paper 1-style essay question (A* exemplar)30 marks
[HARD] 'The benefits of genetic engineering are not worth the ethical risks.' Discuss. (Paper 1 Essay, 30 marks) — full essay of approximately 660 words.
Model answer
The claim that the benefits of genetic engineering are not worth the ethical risks captures a real anxiety: that in gaining the power to rewrite life, humanity may unleash harms it cannot foresee or undo. Yet stated so broadly, the claim is too sweeping. By "benefits" I mean chiefly the prevention and cure of serious inherited disease, and by "ethical risks" the dangers of editing those who cannot consent, of irreversible error, and of deepening inequality. This essay argues that the claim is wrong about therapy but right about enhancement: genetic engineering to cure disease is worth its risks under strict regulation, whereas engineering for enhancement is not.

The case against accepting the claim rests on the sheer scale of suffering genetic engineering could relieve. Many inherited diseases blight or end lives, and the prospect of preventing them is a profound good. The United Kingdom's decision in 2015 to become the first country to legalise three-parent IVF, using genetic material from three people to stop mothers passing on serious mitochondrial diseases, shows that such interventions can deliver genuine medical benefit when introduced through open debate and strict regulation. To dismiss all genetic engineering because of its risks would be to abandon real children to preventable illness, which is itself an ethical cost the claim conveniently ignores. Refusing to act is not neutral; it has victims too.

Moreover, history warns against letting unfamiliarity masquerade as moral objection. When IVF produced Louise Brown in 1978, it was widely condemned as unnatural; it is now a mainstream treatment relied upon by millions. "Unnatural" has repeatedly proved a poor synonym for "unethical", and much of the instinctive revulsion at genetic engineering may belong to the same pattern. On the criterion of relieving proven suffering with consent, therapeutic genetic engineering has a strong claim to be worth its risks.

Nevertheless, the claim contains an important truth once we move from therapy to enhancement. Editing embryos alters not only an individual but all their descendants, who cannot consent, and the long-term effects remain unknown — precisely the situation the precautionary principle tells us to avoid. He Jiankui's 2018 creation of gene-edited babies in China demonstrated the danger: the work was reckless, the risks were unquantified, and the worldwide condemnation and his subsequent imprisonment reflected a judgement that some lines must not be crossed. Beyond safety lies a deeper risk: a slide towards "designer babies" selected for intelligence or appearance, and an equity catastrophe in which only the wealthy can purchase genetic advantage, entrenching inequality and reviving the logic of eugenics. For enhancement, the ethical risks genuinely do outweigh the benefits.

It might be objected that the line between therapy and enhancement is too blurred to police, so that permitting any genetic engineering inevitably opens the door to all of it, vindicating the claim that the benefits are simply not worth the risk. This objection has force, and it explains why vigilance and regulation are essential rather than optional. Yet the contrast between He Jiankui's lawless experiment and the United Kingdom's tightly regulated mitochondrial donation shows the distinction can be drawn and enforced in practice: one was condemned and punished, the other licensed under strict conditions. The difficulty of the line is an argument for guarding it carefully, not for surrendering the benefits of therapy altogether.

In conclusion, the claim that the benefits of genetic engineering are not worth the ethical risks is half right. Judged by whether benefit is proportionate to harm and consent genuine, engineering to cure serious disease is worth its risks when strictly regulated, because it relieves real suffering with consent and oversight. But engineering for enhancement is not worth its risks, because it imposes irreversible, unconsented dangers and threatens to make biology itself a privilege of the rich. The right verdict is therefore neither wholesale acceptance nor wholesale rejection, but a regulated boundary: heal, but do not enhance.
Why this scores
An A* (Band 5) response. It refuses the binary the question invites and sustains a precise, criterion-based thesis (right about enhancement, wrong about therapy) throughout. It supports both directions with a RANGE of specific, accurate, dated examples analysed to advance the ethical argument (three-parent IVF 2015, Louise Brown 1978, He Jiankui 2018), explicitly invokes the precautionary principle and the eugenics/equity concern, and never drifts into explaining the biology. The counterargument (the therapy/enhancement line is unpoliceable) is the strongest available and is directly answered. The conclusion COMMITS to a nuanced, supported verdict ('heal, but do not enhance') rather than sitting on the fence — the decisive AO2 quality, delivered in consistently formal, varied English (AO3).

Key Definitions and Keywords — Science, medicine and ethics

Definitions to memorise and the exact keywords mark schemes credit for science, medicine and ethics answers — sharpened from recent examiner reports for the 2026 Cambridge IGCSE sitting.

Genetic engineering
Examiner keyword
The deliberate alteration of an organism's genetic material to change its characteristics, for example to prevent disease, in plants, animals or humans.
Example
The UK legalised three-parent IVF (mitochondrial donation) in 2015 to prevent inherited mitochondrial disease.
Gene editing (CRISPR)
Examiner keyword
A precise method of changing specific sections of DNA; CRISPR is the best-known gene-editing technology, which made such edits faster and cheaper. (Name it; you do not need to explain the mechanism.)
Example
He Jiankui used gene editing on human embryos in China in 2018, prompting global condemnation.
Cloning
Examiner keyword
Creating a genetically identical copy of an organism. Therapeutic cloning aims to produce tissue for treatment; reproductive cloning aims to produce a whole new individual and is banned in most countries.
Example
Dolly the sheep (1997) was the first mammal cloned from an adult cell.
Stem cells
Examiner keyword
Cells that can develop into many different types of tissue, offering potential treatments for serious conditions. Embryonic stem cells raise ethical debate because obtaining them has involved destroying an early embryo.
Designer baby
Examiner keyword
A child whose genetic characteristics have been deliberately selected or altered for non-medical reasons such as intelligence, height or appearance — the central concern in the gene-editing enhancement debate.
Bioethics
Examiner keyword
The study of the ethical questions raised by advances in biology and medicine, such as consent, the value of life, fairness of access, and the limits of acceptable research.
Clinical trial
Examiner keyword
A carefully regulated study testing a new drug or treatment on people to establish whether it is safe and effective before it can be approved for general use.
Example
The thalidomide scandal led to far stricter clinical-trial and drug-approval requirements.
The precautionary principle
Examiner keyword
The idea that where an action could cause serious or irreversible harm and the consequences are uncertain, one should err on the side of caution rather than proceed.
Example
The precautionary principle is often cited against editing human embryos, whose long-term effects are unknown.
Vivisection / animal testing
Examiner keyword
Experimentation on live animals, especially in medical and scientific research; debated as a clash between human benefit and animal welfare.
The 3Rs (replace, reduce, refine)
A framework for ethical animal research: replace animals with alternatives where possible, reduce the number used, and refine procedures to minimise suffering.
IVF (in vitro fertilisation)
Examiner keyword
A reproductive technology in which an egg is fertilised outside the body before being implanted in the womb; once controversial, now a widely accepted mainstream treatment.
Example
Louise Brown, the first IVF baby, was born in 1978.
Eugenics
Examiner keyword
The discredited idea of 'improving' the human population by controlling who reproduces or by selecting genetic traits; a key ethical warning in debates about gene editing and 'designer babies'.

Common Mistakes and Misconceptions — Science, medicine and ethics

The traps other students keep falling into on science, medicine and ethics questions — taken from recent Cambridge IGCSE examiner reports and mark schemes — and how to avoid them.

✕Writing a science lesson — explaining how CRISPR, cloning or IVF works instead of arguing the ethics
8021 syllabus (Topic 2) — focus is the ethical and social dimensions of science, not technical knowledge
Why it happens
Students who have studied some biology want to show their knowledge, and assume technical detail will impress, when the question is actually about values.
How to avoid it
NAME the advance but never explain the mechanism. Cambridge's focus is the ethical and social dimension, not technical depth. Spend your words on whether it is right, for whom and at what cost — if a sentence is teaching biology, delete it.
✕Using vague, unnamed examples ('scientists can now edit genes', 'science has gone too far')
8021 Examiner Reports — Paper 1: 'unsupported generalisation' is a recurring weakness
Why it happens
Students know the general idea but have not prepared specific, dated examples, so they gesture at evidence rather than providing it.
How to avoid it
Replace every vague reference with a NAMED, dated example — He Jiankui (2018), Dolly (1997), Louise Brown (1978), thalidomide, three-parent IVF (2015). Prepare an examples bank with two to three per sub-theme. Vague references earn nothing under AO1; specific ones are the foundation of every higher band.
✕Describing or narrating a case instead of ARGUING in response to the question
8021 Examiner Reports — 'largely descriptive responses cannot access the higher bands'
Why it happens
Cases like He Jiankui or Dolly are dramatic, so students retell the story rather than using it to test the question's claim.
How to avoid it
After every example, ask 'what does this PROVE about the ethics in the question?'. Use the case to support a judgement, not to inform. Description sits in Band 2; analysis that advances an argument reaches Band 4-5.
✕Omitting the counterargument and writing a one-sided 'science is dangerous' (or 'science is wonderful') essay
8021 Paper 1 band descriptors — Band 5 requires counterarguments acknowledged and addressed
Why it happens
Students have a strong gut feeling about science and argue only their own side, fearing that conceding anything weakens their case.
How to avoid it
Treat a counterargument paragraph as compulsory: state the opposing view at its strongest (e.g. gene editing could cure terrible diseases), then refute or qualify it (e.g. using the therapy/enhancement distinction). The band descriptors require counterarguments to be 'acknowledged AND addressed' for Band 4-5 — omitting it caps your mark.
✕Ending with 'science can be a force for good but can also be misused' instead of a real judgement
8021 Paper 1 guidance — 'a clear, supported conclusion is reached' is required for the top band
Why it happens
Fear of 'getting it wrong' on a contested ethical issue makes students retreat into a balanced-sounding cliche rather than committing.
How to avoid it
Set a criterion earlier (e.g. 'is the benefit proportionate to the harm, and is consent genuine?'), then commit to a verdict with a 'because' (e.g. 'heal, but do not enhance, because...'). Cambridge treats such fence-sitting as an evasion of AO2 and AO3.
✕Using an emotive, alarmist or 'playing God' tone without evidence ('this is terrifying and must be stopped')
8021 Paper 1 band descriptors (AO3) — register and accuracy of written English
Why it happens
Science ethics provokes strong feelings, and students slip into the dramatic, fearful style of headlines and social media instead of reasoned argument.
How to avoid it
Maintain a formal, analytical register and support claims with named examples and clear reasoning. Note that 'unnatural' is not the same as 'unethical' (IVF proves this). Precise vocabulary (consent, proportionate, irreversible, precautionary principle) and calm reasoning score; ranting does not. AO3 is 45% of Paper 1.

Science, medicine and ethics

Detailed Study Notes

At a glance

What you’ll learn

Quick recap

Memorise this

How it’s examined

Take this whole topic with you

1Getting started: building a specific examples bank for science and ethics

2Getting started: decoding a science-ethics question and avoiding the science lesson

3Building confidence: structuring a 'To what extent' essay on ethical limits to science

4Building confidence: writing the counterargument paragraph on gene editing

5Stretch: reaching a committed A* conclusion on a science-ethics question

6Stretch: deploying contrasting examples and analysing, not describing the science

Genetic engineering

Gene editing (CRISPR)

Cloning

Stem cells

Designer baby

Bioethics

Clinical trial

The precautionary principle

Vivisection / animal testing

The 3Rs (replace, reduce, refine)

IVF (in vitro fertilisation)

Eugenics

✕Writing a science lesson — explaining how CRISPR, cloning or IVF works instead of arguing the ethics

✕Using vague, unnamed examples ('scientists can now edit genes', 'science has gone too far')

✕Describing or narrating a case instead of ARGUING in response to the question

✕Omitting the counterargument and writing a one-sided 'science is dangerous' (or 'science is wonderful') essay

✕Ending with 'science can be a force for good but can also be misused' instead of a real judgement

✕Using an emotive, alarmist or 'playing God' tone without evidence ('this is terrifying and must be stopped')