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Interview Hot Topic · Science & Technology

Genomics & gene editing

We can now read a person’s entire genetic code in a day, and even rewrite parts of it. That opens the door to curing genetic diseases — and to some of the hardest ethical questions in medicine. This is a favourite for academic interviews and a rich area for an EPQ, because it rewards clear science and careful reasoning.

Strong EPQ topic Science & Technology 13 min read Last reviewed Oct 2026

Why this comes up

Genomics is where cutting-edge science meets deep ethics — which is exactly why academic interviewers reach for it. They want to see that you can explain the science simply and reason carefully about where to draw the line.

You are not expected to know the biochemistry in detail. You are expected to understand a few key ideas, grasp one crucial distinction (editing a patient versus editing their future children), and weigh the promise against the risks.

How will this be asked?

“Should we be allowed to edit the genes of embryos to prevent disease?”

“What excites or worries you about personalised medicine?”

The embryo question is the classic one — and it turns entirely on the distinction you’ll meet below between somatic and germline editing.

The basics

A quick ladder of terms, from small to large:

  • DNA — the chemical instructions inside almost every cell.
  • Gene — a section of DNA that codes for something, like a protein.
  • Genome — your complete set of genes; your full instruction manual.

“Genetics” usually means studying single genes; “genomics” means studying the whole genome at once. The game-changer is that sequencing (reading the genome) has become fast and cheap — what once took years and billions now takes about a day.

In the UK, Genomics England ran the 100,000 Genomes Project and is now exploring screening newborns’ genomes (the Generation Study). Pharmacogenomics — using your genes to choose the right drug at the right dose — is already entering everyday care.

Zooming in from the body to a cell to DNA to a single gene; your genome is the complete set of genes. You A cell DNA A gene Genome = all your genes
From you, to a cell, to the DNA inside it, to a single gene. Your genome is the whole set — and we can now read it in about a day.

Gene editing & CRISPR

Reading the genome is one thing; changing it is another. CRISPR is a tool that works like a molecular “find and replace” — it can be guided to a precise spot in the DNA to switch a gene off, fix it, or swap it.

The single most important idea for your interview is who the change affects:

Somatic editing changes cells in one patient's body and is not inherited. Germline editing changes an embryo, egg or sperm, so the change is in every cell and is passed to all future generations. Somatic editing Edit cells in the body Helps this patient Not passed on. Widely accepted. Germline editing Edit an embryo, egg or sperm In every cell — passed to all descendants
The crucial distinction. Fixing a sick patient’s own cells is widely accepted; editing embryos changes every future generation — which is where the big ethical fight is.

Two real examples make this concrete:

  • Casgevy — a CRISPR therapy approved to treat sickle cell disease and beta-thalassaemia. It edits a patient’s own cells (somatic). Widely celebrated as a milestone.
  • The He Jiankui case (2018) — a scientist in China edited the genomes of embryos that became babies (germline). It was condemned worldwide as unsafe and unethical, and he was jailed.

Personalised (precision) medicine

Genomics also powers personalised medicine: using your genetic information to predict risk and tailor treatment to you, rather than a one-size-fits-all approach. In cancer, for example, a tumour’s genes can be read to pick the drug most likely to work. Pharmacogenomics can warn that a standard dose might be toxic for you.

The promise is more effective treatment with fewer side effects. The catch is that it needs lots of genomic data, raises privacy questions, and could widen the gap between those who can access it and those who cannot.

The debate

Give the strongest version of both sides. Most of the heat is about gene editing and “designer babies”, so be ready there especially.

The promise

  • Could cure devastating genetic diseases, not just manage them
  • Treatment tailored to the individual, with fewer side effects
  • Prevention — catching risk before illness develops

The concerns

  • Germline edits are permanent and heritable — future people can’t consent
  • The slide from treatment to enhancement (“designer babies”)
  • Cost & access could widen inequality (justice)
  • Genetic data privacy, discrimination, and off-target errors
A spectrum from treating disease, where most people agree, to enhancement, where most people object. Cure a disease e.g. sickle cell Reduce disease risk harder to agree on Enhance traits height, ‘intelligence’
Most people accept editing to cure disease; almost no one accepts editing for enhancement. The hard questions live in the middle — and “where’s the line?” is a brilliant thing to reason about out loud.
How will this be asked?

“Where is the line between treating disease and enhancement?”

There is no neat answer — which is the point. Show you can reason about it: curing a fatal illness feels very different from choosing a child’s eye colour, but conditions like deafness or short stature sit in a genuinely grey zone.

The ethics, through the four pillars

As with most hot topics, the four pillars give your answer instant structure.

Autonomy

Whose choice is it?

A patient can consent to editing their own cells — but a future child cannot consent to germline changes made for them.

Beneficence

The good it could do.

Curing an otherwise lifelong, painful genetic disease is an enormous benefit.

Non-maleficence

First, do no harm.

Off-target edits and unknown long-term effects — which, in germline editing, are inherited for ever.

Justice

Fairness & access.

If only the wealthy can afford it, genomics could deepen inequality — and genetic data could be misused by insurers or employers.

Straight to the point

In the interview

Genomics questions reward a candidate who can explain the science cleanly and then reason about the ethics without panicking. Here’s how to do both.

What the interviewer is really marking

  • Clear science — can you explain genome, CRISPR, somatic vs germline simply?
  • The key distinction — do you grasp why editing embryos is so much more contested?
  • Balanced ethics — promise and peril, with the pillars behind it.
  • Humility — comfort with grey areas rather than forcing a neat answer.

A model answer, in about 45 seconds

Question: “Should we edit the genes of embryos to prevent disease?”

Distinction · “It depends what kind of editing. Editing a patient’s own cells — like the new sickle cell therapy — is widely accepted. Editing embryos is different, because the change is in every cell and passed to all future generations, who can’t consent.”

Both sides · “In favour, it could end terrible inherited diseases before a child is even born. Against, there are real risks: off-target errors that are then heritable, the slide towards enhancement and ‘designer babies’, and unequal access that could worsen inequality.”

Conclude · “On balance I’d be cautious about germline editing until it’s proven safe and tightly regulated — but I’d welcome somatic therapies that are already helping patients. And I’d want these decisions made openly, not by one scientist alone.”

Do & don’t

Do

  • Lead with the somatic vs germline distinction
  • Use a real example (Casgevy, or the He Jiankui case)
  • Reason about the treatment–enhancement line
  • Bring in access and genetic privacy

Don’t

  • Treat all gene editing as one scary thing
  • Get lost trying to recall the biochemistry
  • Give a flat yes or no with no reasoning
  • Ignore future generations’ inability to consent

Where to go next

  • The reasoning here rests on medical ethics — revisit the four pillars & method.
  • Genomics links neatly to AI (both are data-hungry) and to health inequalities — strong candidates connect the three.

Practise this with a real interviewer

In a mock MMI with a Distinction Medic mentor you’ll be pushed to explain the science and defend your reasoning on the ethics — with feedback on both.

Book a free consultation

No commitment required – 30 minute call with a mentor