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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

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