The idea of genetically selecting or modifying babies has roots stretching back decades, but the first real-world milestone came in 1989, when scientists successfully screened a human embryo for a genetic disease before implanting it. Since then, a series of breakthroughs has moved the concept from science fiction to scientific reality, each one reigniting public debate about how far the technology should go.
Where the Term Came From
“Designer baby” is not a scientific term. It was coined by journalists and media commentators to describe a baby whose genetic makeup has been selected or altered to carry (or avoid) specific traits. The phrase took hold in the late 1990s and early 2000s as fertility technologies advanced and the public began grappling with questions about genetic selection. Scientists themselves rarely use it, but it stuck because it captures the central anxiety: that parents could someday customize a child the way they’d customize a product.
1989: The First Genetic Screening of Embryos
The practical starting point for designer babies is October 1989, when Alan Handyside performed the first successful preimplantation genetic diagnosis, or PGD. The technique allowed doctors to test embryos created through IVF for cystic fibrosis before transferring them to the womb. Parents who carried genes for serious inherited diseases could, for the first time, select embryos free of those conditions.
PGD expanded quickly through the 1990s and 2000s. Clinics began offering screening for a growing list of single-gene disorders like sickle cell disease, Huntington’s disease, and Tay-Sachs. In some cases, parents used the technology to select embryos that would be a tissue match for an older sick sibling, producing what the media called “savior siblings.” This was also when ethical alarm bells started ringing. If you could screen for disease, critics asked, what would stop people from screening for traits like sex, eye color, or intelligence?
2013: Gene Editing Enters the Picture
PGD lets parents choose between existing embryos, but it doesn’t change any genes. That changed in 2013, when researchers first demonstrated that a tool called CRISPR could precisely edit DNA in mammalian cells. CRISPR works like molecular scissors, cutting a specific section of DNA so scientists can remove, replace, or modify a gene. Within a few years, labs around the world were testing it in animal embryos, and the question shifted from whether someone could edit a human embryo to when someone would.
In 2015, a Chinese research team became the first to use CRISPR on human embryos in a lab setting. These were non-viable embryos that could never develop into a pregnancy, but the experiment crossed a symbolic line. That same year, an international summit on human gene editing produced a widely discussed consensus statement warning that “it would be irresponsible to proceed with any clinical use of germline editing” until safety and efficacy issues were resolved and broad societal consensus existed about whether it was appropriate.
2016: The First Three-Parent Baby
A separate but related milestone arrived in 2016, when a New York City fertility specialist helped create what’s believed to be the first baby born using DNA from three people. The boy’s mother carried genes for a fatal neurological disorder in her mitochondria, the tiny power-generating structures inside cells that have their own small set of DNA. To avoid passing the disease on, the doctor used a technique called spindle nuclear transfer: he removed the nucleus from the mother’s egg, placed it into a donor egg that had its own nucleus removed, and fertilized the result. The baby carried nuclear DNA from both parents and mitochondrial DNA from the donor.
The procedure was performed in Mexico because U.S. regulators had not approved it. While not “designing” a baby in the sense most people imagine, it represented the first time a child was born with genetic material deliberately sourced from three individuals to prevent disease.
2018: The First Gene-Edited Babies Are Born
The moment that shocked the world came in November 2018. Chinese scientist He Jiankui announced that twin girls, known by the pseudonyms Lulu and Nana, had been born after he used CRISPR to edit their embryos. He targeted a gene called CCR5, which produces a protein that HIV uses to enter cells. His stated goal was to make the girls resistant to HIV infection.
The backlash was immediate and severe. Scientific and ethical organizations around the world issued statements of condemnation. Independent analysis of He Jiankui’s work revealed that neither twin actually carried the specific genetic change he had intended. Instead, each embryo had different, unplanned variations in the gene, raising serious safety concerns about off-target edits and unpredictable effects. He Jiankui was sentenced to three years in a Chinese prison for practicing medicine illegally.
The case became a defining moment in the designer baby debate because it demonstrated that the technology to edit a human embryo and bring it to birth already existed, even if the execution was reckless and the results uncertain.
The Regulatory Response
In December 2018, just weeks after He Jiankui’s announcement, the World Health Organization established a global expert committee to develop standards for governing human genome editing. By July 2021, that committee had published a formal governance framework covering somatic editing (changes to a single person’s cells), germline editing (changes that would be inherited by future generations), and heritable modifications more broadly.
Most countries currently prohibit or heavily restrict germline editing in human embryos intended for pregnancy. The United States bans the FDA from reviewing applications for clinical trials involving heritable genetic modifications. The United Kingdom permits research on human embryos up to 14 days old but does not allow edited embryos to be implanted. China tightened its regulations after the Lulu and Nana case. No country has formally approved the birth of a gene-edited baby.
Where Things Stand Now
PGD remains widely available and is the most common form of genetic selection in reproduction today. Thousands of IVF cycles each year include embryo screening, primarily for chromosomal abnormalities and inherited diseases. More controversial uses, like selecting for sex in the absence of a medical reason, are legal in some countries and banned in others.
Gene editing of human embryos continues in research labs under strict oversight, but no one has publicly attempted another gene-edited birth since 2018. The technology itself keeps advancing. CRISPR tools have become more precise, and newer versions can make single-letter changes to DNA without cutting both strands, reducing the risk of unintended edits. The gap between what’s technically possible and what’s ethically permitted continues to narrow, which is exactly why the 1989 PGD milestone, the 2018 CRISPR babies, and every step in between remain so important to understand.