Embryo selection for IQ and other ‘marginal’ benefits
Might these be more sellable propositions than is often believed?
British science writer Phillip Ball recently wrote a typically useful and accessible article for The Guardian on the ethics of embryo selection using Polygenic Risk Scores (PRSs) in conjunction with Pre-implantation Genetic Diagnosis (PGD). This field raises a number of fundamental questions; such as what people might be prepared to pay for.
As one quoted in the article does, scientists often suggest that small benefits in the field of embryo selection technology would not likely be economic prospects. Unless the scientist perhaps works in a business school such an opinion doesn’t add any value of itself, yet it can be mistaken by the casual reader for an expert opinion. Might the tendency for scientists to do this be a form of risk evasion which directs us to worry less about a potentially worrysome thing because it’s ostensibly unlikely to happen?
Ball’s scientist, Stanford’s Hank Greely, is clearly sceptical that people would be prepared to pay for a 10% reduction in the risk that their child might develop Type 2 Diabetes. The article also refers to a 2019 study which suggested that there would only be a very small benefit extending from selecting for IQ or height. The study in question seems likely to be Karavani et al which suggests a benefit of 3 IQ points or an inch and a half in height if 10 embryos were available.
These broad figures come from a model which reflects average IQ and height variance across embryos produced by the same parents, and factors-in the number of embryos available to select from. Put in simple terms here (the paper itself gives the detail), if we assume for the sake of argument embryo IQ variance of 10 vertical IQ points, then probability would put an embryo selected blind in the middle while a helping hand from PRS might nudge it up to the upper quartile. The more embryos the better, of course. The study suggests a gain of 3 IQ points if 10 were available and 2.5 points is 5 were available.
A Cell article calls this; “limited utility” and paper co-author Shai Carni of Hebrew University, Jerusalem, also plays down the figures in a Scientist article entitled; “Selecting Embryos for IQ, Height Not Currently Practical”.
Leaving aside the regular issues about probability, ethics and, well, science, are scientists correct to assume that there would be little or no demand for such apparently modest benefits?
Very roughly, for IQ if we factor in regression to the mean then two parents with IQs of 130 might reasonably expect embryos mainly across the range 110 to 120. The probablistic benefit from PRS might, for the sake of argument, therefore be to move the 115 midpoint chance provides up to perhaps 118.
Whether anyone would be preparted to pay for this is a question for business folk, of course, but its worth considering the fortunes some people pay for small benefits in livestock reproduction which can nevetheless represent critical margins. Think of racehorse or polo horse breeding. Also, people with plenty of cash are often more generally very aware of how marginal benefits can shift the odds their way big time when it counts. A sales pitch which stressed not only the probablistic 3 point gain but also stressed the lower chance of a result at the bottom end could be very fruitful with them.
Imagine two wealthy professional parents with IQs around 130. They might well worry that a child with an IQ of 110 would find it hard to operate vocationally at their parent’s level in future, while one close to 120 quite possibly could given the right environment. Again, these are just probabilities; but as Ball notes in his article, all of the educational choices we make for our children are probablistic.
The real business question here revolves around whether the cost-benefit analysis leads to an economic prospect. Seen in terms of well-off people trying to tip in their favour the odds of avoiding the worst outcome (in our example, around 110) and achieving the best (close to 120) this seems at face value a pretty sellable proposition.
Ball’s article also mentions IVF. Here, clients select between donor embryos using knowledge of the donor’s traits. In respect of IQ, the potential benefits are clearly not limited to 3 IQ points; choosing between donors can realistically mean a probablistic difference of a dozen IQ points or more. PRS could add 3 points in the same way as above and quite likely more by enhancing the selection methodology. It is easy to imagine PRS for IQ in future becoming a relatively inexpensive add-on to already-expensive IVF.
Finally, it is further off and may never happen for humans, but Iterated Embryo Selection (IES) is already possible with small animals. If it becomes available for humans it could yield a similar scale of benefit to natural parents (or even a single parent) as is presently available to those using donor eggs.
Here, stem cells are extracted and put through the full cycle over a period of around 6 months, then stem cells are extracted from the new embryo and repeat. If 3 IQ points were available at each cycle, then this could be multiplied by the number of cycles to yield a very large benefit indeed. Oxford’s Professor Nick Bostrum has an interesting paper which gives more detail.
Leaving IES aside, it seems clear that there could there be a ready market for people going through IVF to pay for an add-on IQ option likely to yield several IQ points while avoiding the lower end of possible outcomes. But is 3 IQ points enough to entice people capable of natural births to go through the travails of PRS and PGD? Maybe, but perhaps most likely amongst the rich and those higher professionals keen to avoid at the lower end of their natural embryo variance.
For now, companies like Genomic Predication do not offer PRS for IQ or height as it is too controversial. But in the end, most business decisions are a funtion of price. If, once reputational risk is priced in, there is room for a return which fits the company’s profile, a rich vein of potential profit might well exist. Scientists quick to rule this out might want to pop along to that big block with the nice carpets sponsored by Acme Ltd to check their theory out…..
