A designer baby is a baby whose genetic makeup has been selected or modified before birth, typically through in vitro fertilization (IVF) combined with genetic screening or editing tools. The term covers a spectrum: from choosing embryos less likely to develop certain diseases all the way to directly editing DNA to change specific traits. In 2004, “designer baby” became an official entry in the Oxford English Dictionary, reflecting how central the concept had become to public debate about biotechnology.
How Genetic Selection Actually Works
There are two fundamentally different approaches to creating a designer baby, and they’re often confused. The first, which already exists commercially, is embryo selection. During IVF, multiple embryos are created, and each can be genetically tested before being implanted. This doesn’t change any DNA. It simply lets parents and doctors choose which embryo to use based on its existing genetic profile.
The most common version of this is called preimplantation genetic testing, which screens embryos for serious single-gene disorders like cystic fibrosis or sickle cell disease. A newer and more controversial form uses polygenic scores to estimate an embryo’s statistical risk for complex conditions. Companies like Genomic Prediction already offer screening for type 1 and type 2 diabetes, breast cancer, prostate cancer, coronary artery disease, hypertension, and schizophrenia. Another company, Orchid Health, covers many of the same conditions plus Alzheimer’s disease and inflammatory bowel disease. At least one company, MyOme, has provided research participants with embryo scores for traits like cognitive ability, educational attainment, and even subjective well-being.
The second approach is direct gene editing, most commonly using a tool called CRISPR-Cas9. This technology works like molecular scissors: it can cut DNA at a precise location and either delete, repair, or replace a specific gene. In 2017, a team at Oregon Health & Science University used CRISPR to correct a mutation that causes a heritable heart condition in human embryos created through IVF. The embryos were viable but were not implanted.
What’s Possible Today vs. Science Fiction
The gap between what people imagine when they hear “designer baby” and what’s currently feasible is enormous. Selecting an embryo to avoid a disease caused by a single gene mutation is routine and reliable. Thousands of families use it every year. But traits like intelligence, height, and athleticism involve hundreds or thousands of genes interacting with each other and with the environment. No genetic test can reliably predict these outcomes, and no editing tool can reshape them in a meaningful way.
Polygenic screening is the closest thing to “trait selection” available today, and its predictive power for complex traits remains limited. A polygenic score might slightly shift the statistical odds for a condition like diabetes, but it cannot guarantee a specific outcome. For traits like intelligence or attractiveness, the science is nowhere near precise enough to deliver on the designer baby promise that dominates popular culture.
The Safety Concerns Are Real
Gene editing in embryos carries two major technical risks that remain unsolved. The first is off-target effects: CRISPR can sometimes cut DNA at the wrong location, potentially disrupting genes that have nothing to do with the intended edit. If those unintended cuts land in regions that control cell growth or development, the consequences could be serious. Some research suggests the rate of these errors is low, comparable to naturally occurring mutations, but “low” is not “zero,” and the stakes in a developing embryo are high.
The second risk is mosaicism. When CRISPR is applied to a fertilized egg, the edit doesn’t always take effect before the cell starts dividing. The result can be an embryo where some cells carry the edit and others don’t. This makes the outcome unpredictable: the genetic change might be present in some tissues but absent in others. Researchers have found that timing the edit before DNA replication begins can reduce mosaicism, but eliminating it entirely remains a challenge.
Both risks are compounded by the fact that changes to an embryo’s DNA are heritable. Unlike gene therapy performed on a living person (which affects only their cells), edits made at the embryo stage get passed to every future generation. A mistake wouldn’t just affect one person. It would ripple through a family line.
The He Jiankui Case
The most infamous real-world case happened in November 2018, when Chinese scientist He Jiankui announced that twin girls had been born from CRISPR-edited embryos. He had attempted to disable a gene called CCR5 to make the children resistant to HIV. The scientific community’s reaction was overwhelmingly negative, for several reasons.
The editing was incomplete in at least one of the twins, meaning the intended HIV protection may not have worked as designed. Disabling CCR5 is also known to increase vulnerability to West Nile virus and severe influenza. The procedure violated China’s existing regulations on embryo research, and He Jiankui had not provided adequate informed consent to the parents. Some scientists who reviewed his data also noted that the edits he made to CCR5 could potentially affect cognitive function, raising the possibility that he had inadvertently (or intentionally) altered the children’s brain development. He was sentenced to three years in prison.
Where It’s Legal and Where It’s Banned
No country on Earth currently permits clinical use of heritable gene editing in humans. A 2020 survey of 96 countries found that 70 have clear policies against it. Eleven countries, including China, India, the UK, Japan, and the US, allow basic research on embryo editing under specific conditions, but none have approved transferring an edited embryo into a womb to establish a pregnancy.
In the US, the FDA’s authority covers gene therapy products, and as of January 2024, the agency has approved numerous clinical trials for editing genes in living patients (somatic editing) but zero trials involving heritable changes. The UK permits research on human embryos for up to 14 days, but its fertility regulator has not approved any clinical applications of embryo editing. China’s 2024 ethical guidelines state explicitly that “any clinical research on heritable genome editing is irresponsible and not allowed.”
Embryo selection through genetic testing, by contrast, is legal and commercially available in many countries. The US has relatively few restrictions on which traits can be screened for, while countries like the UK regulate more tightly, generally limiting screening to serious medical conditions.
The Cost of Genetic Screening
For families pursuing IVF with genetic testing, the costs add up quickly. In the US, testing embryos for chromosomal abnormalities typically runs $4,000 to $5,000 per cycle on top of IVF fees. Testing for a specific inherited disease is more expensive, commonly $7,000 to $12,000 per cycle, because it requires custom lab work to identify the family’s particular mutation. When you factor in the additional cost of a frozen embryo transfer, the genetic testing portion alone can total $8,000 to $10,000. Some clinics offer lower pricing: CNY Fertility, for example, lists testing at $2,000 to $3,000 plus transfer fees.
These costs mean that even the selection-based version of designer babies is accessible only to people who can already afford IVF, which itself typically costs $15,000 to $20,000 per cycle. This raises one of the most persistent ethical concerns about the technology: that it could deepen existing inequalities if wealthier families gain access to genetic advantages that others cannot afford.
Where the Public Stands
Public opinion draws a sharp line between medical and cosmetic uses. A 2022 Pew Research Center survey found that 71% of Americans favor using gene editing to treat serious diseases a person already has, with only 10% opposed. But 74% oppose using gene editing to change a baby’s physical appearance, with just 5% in favor.
The middle ground, editing embryos to reduce a baby’s future risk of disease, splits people almost exactly in half. Thirty percent of US adults call it a good idea for society, 30% call it a bad idea, and the rest are unsure. When asked whether they’d want this for their own baby, 48% said yes and 49% said no. That near-even divide captures the tension at the heart of the designer baby debate: most people support fixing clear medical problems but grow uncomfortable as the technology moves toward choosing traits that fall within the range of normal human variation.