Will Progressives Defend In Vitro Gametogenesis?

On identity politics and skepticism about enhancement

Photo by Nick Fewings

In vitro gametogenesis (IVG) is the process of producing sperm or eggs in a laboratory. While sperm is not a scarce resource, eggs are. IVG could remove the need for egg extraction during in vitro fertilization (IVF) and provide same-sex couples with the possibility of having biological children. Additionally, IVG in humans would be exceptionally important for genetic enhancement. It would be so impactful that it would qualify as one of the most important scientific achievements in human history.

The number of embryos is a significant bottleneck for trait selection when choosing embryos. Any process that drastically increases the number of available eggs will enable the creation of much more embryos. More embryos enable considerable gains when selecting embryos for desirable qualities like health, wellness, or cognitive ability. The expected gain for a normally distributed trait like height or IQ is proportional to the square root of the logarithm of the number of embryos (Karavani et al., 2019). As the number of available embryos increases, the expected return for each additional embryo in the batch grows smaller. When eggs are highly numerous thanks to IVG, returns from more embryos will be small, but overall gains will be very large. At that point, increasing polygenic scores will be a more worthwhile avenue for better returns from embryo selection.

Genetic enhancement technology has the potential to increase human and animal welfare massively. Polygenic screening is currently used to select embryos primarily for health, but it can also be used to select for traits like cognitive ability. Upon hearing this, some progressive-minded people have a strong instinct to worry about inequality. The wealthy will have more ability to get access to new technology, and that is not fair in their view. Recognizing and acknowledging the unfairness is not bad. The healthy expression of this impulse is to want to increase the availability of beneficial technology. The unhealthy expression is to want to ban this technology or regard practitioners as unethical.

In some cases, the moral disapproval of polygenic screening motivates an unwarranted level of skepticism. Some criticisms are not applied equally to other screening methods. The alternative to polygenic screening is randomness or visual inspection. Critics say PGT-P is unproven, unethical, or not worthwhile. However, often they neglect to make relative comparisons between methods of choosing embryos. If they did, they would reveal that PGT-P is more ethical, proven, and useful than the alternative of visual embryo inspection. Even natural conception, without any form of screening, does not face the scrutiny of these critics even though it results in children with genetic disorders. Rather than considering the whole context or trying to perform a cost-benefit analysis, some skeptics leverage every criticism they can.

Will in vitro gametogenesis face the same type of unfair criticism as PGT-P? Perhaps not from progressives. It seems likely that many religious conservatives will be opposed to IVG because it is playing God or unnatural. They may also be extra-motivated if they are opponents of same-sex marriage. Since IVG will facilitate same-sex biological children, progressives may be highly motivated to defend the technology as safe, despite many having a revulsion toward the gains from the genetic selection this would enable. Rather than taking a highly skeptical angle as many journalists do toward “designer babies” and embryo selection, I suspect and hope IVG will be celebrated in the media. It is somewhat cynical to think that scientific skepticism from the public is primarily ideologically motivated, but upon a brief reflection, it is clear that this cynicism is warranted.

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