Genetic Testing of Embryos Raises Ethical Questions About 'Designer Babies'

In an era focused on self-optimization, the drive for control has extended to reproduction, with emerging technologies allowing prospective parents to screen embryos for a wider range of genetic predispositions. This advancement, particularly preimplantation genetic testing for polygenic risk (PGT-P), aims to identify embryos with a lower likelihood of developing complex conditions such as heart disease and diabetes.

Journalist Kristen V. Brown, author of "The Immortal Womb: The Centuries-Long Quest to Control the Female Body and Hack Human Reproduction," explained that PGT-P builds upon basic genetic screening, which typically checks for single-gene disorders like Down syndrome. However, PGT-P analyzes the combined effect of numerous genes to assess risk for conditions influenced by both genetics and environment. "If you go through IVF, very often they’ll have you do a basic genetic screening that can detect things like Down syndrome. This screening takes that up a notch," Brown stated. "It uses that same preimplantation genetic testing to look for the likelihood of complex genetic conditions — stuff like heart disease, like diabetes — in order to, quote, ‘let people have the healthiest baby.’"

Beyond disease predisposition, the technology is also being marketed for its potential to screen for traits such as height, eye color, and even intelligence. This expansion into non-medical characteristics raises significant ethical concerns, drawing parallels to eugenics. The concept of a "Gattaca stack," a term coined by tech executive Brian Armstrong, envisions a suite of reproductive technologies—including in vitro gametogenesis (creating eggs and sperm from skin cells), PGT-P screening of numerous embryos, and artificial wombs—to engineer "perfect" human beings.

While the desire to have a healthy child is understandable, the implications of selecting embryos based on a complex array of genetic factors are being widely debated. "I think that one of the things that we don’t talk about enough is that the genome is complicated. You can’t actually just go in there and be like, ‘I want a tall baby with blue eyes and a great laugh,'" Brown noted. She emphasized that many mainstream medical societies and geneticists remain against PGT-P for embryos, citing the technology's flaws and the inherent unpredictability of human development.

Currently, embryo editing to alter genes remains illegal in the United States and most other countries due to safety concerns. However, the interest in such technologies, particularly for preventing severe genetic diseases, is growing. The argument for enabling parents who face difficulties in obtaining healthy embryos through repeated IVF cycles is that embryo editing could offer them a better chance.

Brown also pointed out that societal practices, such as screening against Down syndrome early in pregnancy, have already introduced complexities. She noted that parents of children with Down syndrome have argued that such screening constitutes a form of eugenics. As genetic technologies advance, similar ethical questions are being applied to an increasing number of conditions and traits.

Despite the allure of optimizing reproduction, Brown stressed that human development involves numerous variables that cannot be fully controlled. "I think that becoming a parent is an exercise in giving up control, and that’s easier for some people than others," she said. "I have so much sympathy and empathy for people who are trying to stack the deck. But I think there are just so many variables when it comes to human reproduction that we are never going to be able to fully control the process, as much as we might want to and as appealing as that might sound."