Henry Greely is a bioethicist and Deane F. and Kate Edelman Johnson Professor of Law at Stanford University. His book, The End of Sex and the Future of Human Reproduction, comes out in paperback this spring. In it, he writes about how sperm and eggs derived from stem cells, and improved genome sequencing technologies, will combine to create "Easy PGD." He envisions this as a modernization of current pre-implantation diagnosis technology, where fetuses can be surveyed for genetic diseases before they develop further. We corresponded by email late last year, talking about new developments, how laypeople might approach Easy PGD, and why new technology sometimes scares me.

Dan Samorodnitsky: The End of Sex was first published May 2016 (the paperback comes out on April 9). Has anything happened since then, politically, scientifically, or otherwise, to change your view of how the potential future of Easy PGD will play out?

Henry Greely: Nothing big so far.

What a thing to say in 2017. I'm surprised! In my mind, there have been positive developments (like the child born from a frozen embryo almost as old as her mother) and negative developments (like Ohio banning abortion in reaction to a Down syndrome diagnosis) for Easy PGD's future. Are they just bumps in the road?

The long-frozen embryo is interesting, but not for Easy PGD – except, I suppose, as a balm for the consciences of some who don’t want to destroy their leftover embryos. They can keep them frozen indefinitely in the hope that sometime, somewhere, someday, someone will want to make babies of them. Embryo adoption, though, seems to be a very, very small niche. I haven’t found any numbers, but I’m not sure more than 100 babies have arrived that way; I’d be shocked if it were a thousand. Total. Out of roughly 4 million babies per year in the US.

As to the Ohio law, it is mainly of Easy PGD interest in that it, like the laws in North Dakota and Indiana (the latter is currently enjoined by a federal judge as the Ohio law is likely to be) cover abortion, NOT PGD. The US right-to-life movement has not yet shown any interest in going after embryo destruction in reproduction.

Progress on making gametes from iPSCs [induced pluripotent stem cells, which are stem cells derived from other cells rather than harvested from an embryo] would be exciting, but I didn’t see much this year. Cheaper WGS [whole genome sequencing] would be another good sign and there are a few signs of falling price. There’s now a company offering SNP [single nucleotide polymorphism, a mutation at one base in a gene] chip multi-genic analysis at the PGD stage. That worries me because I think the SNP chip analyses are awful. How real that company is is not clear to me.

Reading the news, you could believe that in 2017 any disease can be predicted or CRISPR'd away with perfect accuracy. How can a layperson evaluate what is and isn’t a real advance in genetic testing?

That’s a tough one. They need to know that almost nobody has a genetic disease that can be predicted perfectly (or even almost perfectly). There are several thousand of them, but they are all rare – at this point, well under 5 percent of babies (getting sick at some point during their lives, so counting late onset diseases like Huntington’s), I believe. They’ve got to look at specific diseases – and there are a lot of online resources.

In the book, you discuss the “right to make gametes,” whether the old-fashioned way or through stem cells/nuclear transfer, in the context of legal obstacles to Easy PGD. As far as I can tell, this right has not been directly addressed by an American legislature. Would it need to be directly addressed for Easy PGD to become reality?

It hasn’t been. But, in general in the US, whatever is not forbidden is allowed. The FDA would be a regulator on safety and efficacy, but otherwise new laws would have to be passed to stop or limit it.

My biggest concern, and the thing I kept coming back to reading this book, is what will realistically happen when dealing with cases beyond those that have a strong genetic component (chromosomal aberrations, BRCA cancers, some kinds of prion diseases)? It strikes me as unlikely that many diseases will be able to be selected for or against with much certainty, and the idea of trying to select from a batch of embryos with some uncertain chance of not having a particular disease, or being a great athlete, or anything else, terrifies me. Do you feel more optimistic about Easy PGD's practicality in more uncertain cases?

I agree with you the most diseases will not be powerfully predictable through genetics. Maybe 10 percent of us will eventually have such diseases (double the current 5 percent for more genetic knowledge). But why does it terrify you? Poorly informed people will make decisions on weak to non-existent evidence, but right now we get a random selection from the embryos a couple could possibly make. Well informed/counseled people will be told - “this is extremely weak evidence, you should ignore it and concentrate on the things that are, in fact, pretty good.” Maybe that means knock out five or 10 out of 100 embryos and then pick among the rest based (knowingly) on weak evidence or even randomly. Why is that worse than the status quo?

Honestly, I don't know why it terrifies me. I agree that picking embryos on weak evidence or randomly isn't worse or even that different from the status quo. Maybe it's a gut reaction to an uncertain future, or a feeling that maybe something untoward might happen? There's a bit of a power imbalance between doctor, counselor, and patient in this scenario. Is mine a common a reaction to making predictions about the future?

I do think there is an odd and common reaction to being more upset by chosen outcomes than chance ones. Choice confers responsibility in a way that chance/fate seems to avoid. I think that’s the impulse behind the precautionary principle. But not choosing IS choosing - maybe this comes back to the deep philosophical action/inaction distinction, as old as it is illogical.

Do you think there are any categories of selection (disease, appearance, gender, sexual orientation, etc.) that specifically should be regulated?

Different people will want different things. Different cultures will care about different things. I wouldn’t call them wrong for refusing to use, or allow its use, for some things. I probably wouldn’t regulate anything except possibly parents (crazy, weird parents, but it’s a big world and there are some) choosing affirmatively an embryo with a very serious genetic disease (Tay Sachs, say). You’d have to be crazy to do that, I would happily condemn them as ethically/morally wrong, but I’m not sure I would ban it. Too hard to define which diseases are serious enough to overrule parental choice.

Will doctors who perform Easy PGD have legal trouble, or need some form of malpractice insurance, if children they help parents select develop diseases that the parents tried to select against?

Sure. All doctors (and lawyers, and accountants, etc.) need malpractice insurance. Part of it is for handling “bad” suits - the insurance pays for the lawyer who gets the case dismissed when you can prove you told the parents there was a, say, 20 percent chance that the baby would have X, and they are mad that the baby had X instead of the 80 percent. But sometimes doctors, counselors, and labs will make mistakes and they will and should be liable for those. Insurance would be useful!