The Future of In-Vitro Fertilization and Gene Editing (Psychology Today)
"The Eminents" interview with Stephen Hsu.
MN: Would you explain polygenic complex traits embryo selection in more detail?
SH: Most human traits (e.g., height or cognitive ability) and most disease risks (e.g., for diabetes or heart disease) are polygenic -- they depend on many different genetic loci. For the first time, thanks to very large datasets and advances in AI / machine learning, we have genomic predictors for these traits. Our height predictor is accurate to a few cm! Individuals who are outliers for risk -- for example, have 5 or 10 times greater probability of heart disease than the typical person -- can now be identified using inexpensive genotyping.
Many although not all parents using IVF are confronted by an “embryo choice” problem: They have more viable embryos than they intend to use. For these parents, it is useful to have additional information about each embryo, such as whether it is at high risk for certain health conditions. Each year, a million embryos are genetically screened worldwide. Most of the time, this is just a screen for chromosomal normality (e.g., against Down’s Syndrome), but with better technology, we can screen against many mutations and complex disease risks.
MN: What ethical safeguards need to be in place before this kind of technology is put to use?
SH: The birth of the gene-edited baby girls has brought this issue to the forefront. While bioethicists and researchers have already thought through many of the ethical questions (the obvious criteria are safety, effectiveness, and benefit to the child, as well as implementation that would ensure net benefit to society, for example, the procedure’s cost being covered by health insurance provided to the poor), the average person has not. It seems important that there be a high level of public understanding of and consensus about these new technologies before widespread use.
However, It is probably too much to ask that each country come to the same conclusions as to what is permissible or best. Hence I think we will see a patchwork of legal and regulatory practices.
MN: Since this is Psychology Today I want to ask about cognitive ability and personality traits. Can we predict these from genotype? How will this be used in IVF?
SH: From genotype, we can predict cognitive ability (i.e., IQ) with correlation r ~ 0.3 to 0.4, which is as well as standardized tests like SAT or ACT predict college performance. This is nowhere near the accuracy of, for example, height prediction. However, despite the SAT's only moderate accuracy, it is easy to understand why colleges are reluctant to admit students with low (say, bottom 10%) scores, and generally very enthusiastic about students with high scores. It’s similar with the current genomic predictors. We can identify embryos that have unusually high risk of intellectual disability but we can’t reliably rank-order embryos that are in the normal range.
At the moment, the situation is even worse for predicting Big-5 personality traits, such as conscientiousness or extraversion, even though we know those traits are fairly heritable. I expect the situation for all psychological traits to improve drastically in the near future as more data become available.
At present, we can apply genomic prediction to cognitive traits in the same way we apply it to disease risk -- to warn parents about embryos that are outliers in risk. In the future, we may be able to rank-order embryos, although this would raise further important ethical issues that need to be explored. By comparison, we’ve found in our testing that we correctly predict height ordering between two same-sex siblings 80 to 90 percent of the time. I don’t see any reason we won’t get to this point with IQ, but it may take some years.
MN: Tell me something about yourself that people might find surprising.
SH: I’m a huge fan of Mixed Martial Arts (MMA) and jiujitsu. I learned judo growing up, and got into Brazilian jiujitsu and MMA in the early 1990s when the UFC first started. I trained pretty seriously in the US and Japan, including with some professional fighters. Jiujitsu is like chess with the human body -- move and countermove, dominate position, then force a submission.
Perhaps the most beautiful thing about jiujitsu is that one can submit the opponent without either getting hurt. It would be great if intellectual / scientific disagreements worked the same way :-)