What's This Actually About?
CRISPR and the Gene Revolution
Hook: the first Casgevy patient in 2023 — and He Jiankui's CRISPR babies in 2018. What these two events together reveal about the technology.
Learning Material
1 pagesLesson 1 — What's This Actually About?
Understanding the Complex: CRISPR and the Gene Revolution
It was November 28, 2018. A few dozen scientists had gathered in Hong Kong for an international gene editing conference. He Jiankui, a 35-year-old Chinese biophysicist, walked to the podium.
He announced that two baby girls had been born with edited genomes.
He had used CRISPR — a gene-editing tool developed just six years earlier — to modify embryos before implantation. The twins, whom he called Lulu and Nana, were the first human beings born with deliberately altered DNA. The edit was intended to make them resistant to HIV.
The room was silent.
David Baltimore, who won the Nobel Prize in 1975 and had organized an international summit on gene editing just three years earlier, said afterward: "I'm deeply uncomfortable with what was presented here." Other scientists used stronger language. Some called it reckless. Several called it unethical. A few called it a crime.
He Jiankui was subsequently convicted by a Chinese court of illegal medical practice. He was sentenced to three years in prison and fined three million yuan. Lulu and Nana are alive. The changes in their genomes are permanent. They will be passed on to any children they might have.
Nobody asked them.
Fast forward five years to December 2023.
Victoria Gray was 34 years old when she walked into a clinic and received an infusion of her own blood cells — blood cells that had been removed from her body, had their DNA edited using CRISPR, and had been returned. Gray had suffered from sickle cell disease since birth, a genetic blood disorder that causes excruciating pain crises and organ damage. After the treatment, her pain crises stopped. She became the first patient treated with Casgevy, the world's first approved CRISPR therapy, cleared by the FDA in December 2023.
Victoria Gray's cells were edited outside her body. The changes affect her and only her. When she dies, the edited DNA dies with her.
Lulu and Nana's cells were edited before birth. The changes are in every cell of their bodies, including — potentially — their eggs.
Same tool. Completely different act.
This course is about that tool and that distinction.
CRISPR-Cas9 is often described as "molecular scissors" — a technique for cutting and editing DNA with a precision that earlier biotechnology couldn't approach. The description is approximately correct. The analogy, like all analogies, has limits.
What it has enabled in the decade since its invention is not a single thing. It is a range of things — from curing inherited blood disorders in living patients (Casgevy), to editing embryos in ways that affect all future generations (He Jiankui's experiment), to theoretically driving entire species toward extinction or modification in the wild (gene drives). These aren't variations on a theme. They're fundamentally different interventions with fundamentally different ethical weights.
The public conversation about CRISPR mostly collapses them into one. Either CRISPR is medical progress — the cure for cancer, sickle cell, muscular dystrophy, fill in the disease — or it's playing God, designer babies, eugenics reborn. Both framings exist. Both miss the specificity.
This course tries to provide that specificity.
The central question we're answering:
What is CRISPR really — and why is it simultaneously the most promising medical technology in decades and the most serious biosecurity risk of our time?
By the end of this course, you'll be able to read a headline about CRISPR and immediately ask the right questions: Is this somatic or germline? Is this therapeutic or enhancement? Who funded the research, and what do they stand to gain? What was the regulatory pathway? What does "off-target effects" mean and why does it matter?
Those questions don't require a biology degree. They require knowing what to look for.
One more thing before we start.
This is the most ethically contested course in this series. Several lessons deal with questions where the science is clear but the values are genuinely disputed — and where reasonable, informed people disagree based on different frameworks. We will present those disputes fairly. We will not tell you what to think about germline editing, designer babies, or gene drives. That's your job.
What we'll give you is the vocabulary and the structure to think about them better.
Next lesson: Why should you care? — Three reasons CRISPR matters beyond medicine.
Reading time: approx. 8–9 minutes