Published by
Stanford Medicine

Fertility, Genetics, Pregnancy, Stanford News

The end of sex?

The end of sex?

Somebody, somewhere, must have been having sex during the noon hour yesterday. But inside a small classroom in Stanford’s Li Ka Shing Center, about 30 attendees were sitting in a U-shaped formation listening intently as Stanford law professor Hank Greely, JD, made an astounding prediction: Within the next 50 years or so, Greely said, the majority of babies in developed countries will be spawned in IVF clinics.

Greely is chair of the of Stanford Center for Biomedical Ethics’ steering committee chair as well as director of Stanford’s Center for Law and the Biosciences. He sat in on a panel discussion I moderated last year about the societal issues posed by new reproductive technologies. Clearly, he’s been thinking about this a lot.

The provocative title of Greely’s talk, “The End of Sex,” was not meant to imply the demise of sexual relations or gender differences or the basic one egg/one sperm requirement. Rather, he said, sexual intercourse as a mode of conception will become outmoded, thanks to steady improvements and cost reductions in whole-genome sequencing, analyzing an embryo’s genome in a dish without impairing the embryo’s viability, and making gametes from iPSCs (induced pluripotent stem cells) generated from easily reached tissue such as skin. Like embryonic stem cells, iPSCs can differentiate into every one of the 200-odd cell types that make up the human body. (And if gametes can be begotten from skin via iPSCs, age and even gender will no longer pose a barrier to creating thousands of embryos to pick from.)

Four or five decades is a long time in the life-science business. And so a half-century hence, said Greely, “most children will be conceived in IVF clinics” – as selecting your kids for health traits gets not only cheap and easy but outright encouraged by insurance companies and governments trying to rein in health-care expenses. Tossing a measly $5K into the kitty for prenatal genetic diagnosis to predict other, not strictly medical traits from height to sociability to IQ will prove irresistible for people already ready to fork over an extra twenty grand a year for the right preschool, Greely suggested.

Putting aside some truly gnarly ethical issues (eggs or sperm from two-year-old girl’s skin? a dead man’s? a pilfered toothpick?) not to mention profoundly deeper concerns (see The Abolition of Man, by C.S. Lewis), I’m skeptical for other reasons. The notion that a majority of babies will originate from a lab procedure depends on the procedure’s perceived utility: People have to believe that optimizing embryos absent serious health concerns actually makes for better babies. But would it?

Here’s the thing: PGD, properly performed, hasn’t yet been shown to impair embryos’ progress to babyhood. And the follow-up necessary to ensure that no long-term harm occurs awaits several more decades of careful follow-up. In PGD, one cell is teased from the eight or so that compose an early embryo, then subjected to genetic scrutiny. The assumption that the remaining cells can fill in for the missing one, is just that: an assumption. Serious researchers, such as Magdalena Zernicka-Goetz, PhD, of the Gurdon Institute, have shown position-dependent differences in embryonic cells at the earliest stages of development.

Plus, many of the most interesting inherited human traits owe to not one, but scores or hundreds of genes working in concert. Many genes are pleiotropic, so an improvement in one desirable trait (say, athletic prowess) comes at the expense of another (say, intelligence). Besides, there’s more to a human cell’s hardwiring than mere DNA. Cells’ properties (and those of the person those cells compose) depend on activation levels of each gene in each cell, which in turn depend on epigenetic settings – chemical rheostats – that are themselves inherited, to some degree, along with the DNA.

Anyway, no amount of genetic selection can forecast with any accuracy the environment in which a newborn’s genetic program will play out. Today’s “lethal disease” becomes tomorrow’s nuisance. I suffer from a genetic defect that surely would have caused my early death 3,000 years ago. It’s called “nearsightedness”. Big deal; I wear contact lenses. Who knows what “the just-right genome” will look like 50 years from now?

Previously: Sex without babies

4 Responses to “ The end of sex? ”

  1. Jennifer Lahl Says:

    Sadly, this is an instance where technology has kept up with hubris.

  2. Stuart Nicholls Says:

    Once again this appears to be a case of scientific hubris. I certainly would suggest that the number of children conceived through IVF and so one may increase, but I very much suspect that that they will still be in the significant minority.

    look at the UK for example. In 2009, 232 patients underwent 288 PGD treatment cycles. In 2008 this was 214 cycles with 182 patients, totaling 66 babies. Even with IVF totals there were 44,275 cycles (2006), 46,829 cycles (2007), and 50,687 cycles (2008)( These led to 12,596; 13,672; and 15,082 babies. A small proportion of the 758,000 born in 2007-2008 ( Indeed a simple forecast based on trend data between 1991 and 2008 ( suggests that within 50 years levels would reach somewhere in the region of 55,000 births. Some way off “Most” of the present births (let alone an increase in birth rate within the general population).

    One also needs to consider practical issues: regulation – could it cope with such a dramatic increase? System capacity – are there enough clinicians and facilities? These as much as the ethical, social and legal issues are likely to impact on the prediction.

  3. Bruce Goldman Says:

    Stuart, thanks for your comments and your prodigious sourcing. I would only point out that Greely was basing his prediction on a radical departure from the current trends in IVF you’ve noted. Greely claims that a massive climb in the percentage of offspring produced by pre-implantation-genetic-diagnosis-guided IVF will be fueled by a)the steep and continuing drop underway in complete whole-genome sequencing; b) the ability to produce massive amounts of gametes based on iPS-cell technology; and c) the upward ratcheting of the middle-class beggar-thy-neighbor competition that has parents applying years ahead of time to get their kids into the right preschool for many tens of thousands of dollars a year.

    Like you, I am skeptical that this will come to pass — due to scientific barriers I tried to outline in my post, above. But the real question that has to be dealt with — even if it applies to a far lower number of attempts at producing the perfect child — is this: Just because we can, does that mean we should?

  4. Melded Says:

    I agree with this completely. It’s a matter of the basic logic of survival in an increasingly complex world.

    The world is dangerous, clearly. Between Monsanto, Big Pharma, & Big Oil it’s a wonder we can still reproduce at all. In a lab everything is controlled, it’s safer, basic checks can be done to ensure a healthy happy baby.

    Most of us want it all, we want happy lives, happy families, happy all the time. This is just the latest shoe to fall in our quest for unlimited happiness. We want perfection, we value perfection, perfect beauty, perfect elegance, perfect voices.

    The best course I think is to accept it and promote it, it’s an interesting and valid course for humanity to take, it could mean the elimination of all disease and nearly all human suffering. Philosophically there are questions, but I can’t see a rational moral quandry. If a person were going to be born diseased, and suffering, would they want that? Really? If you could modify the embryo to remove the disease, why wouldn’t you?

    It makes sense in too many ways. We’re at the bottom of the curve, like everything it will have it’s moment of exponential growth, we just haven’t hit the turning point yet.


Please read our comments policy before posting

Stanford Medicine Resources: