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The end of sex? Maybe not just yet

Will in vitro fertilization gradually morph from a blessing for infertile couples to a preferred pathway to parenthood?

In January, I wrote about a talk given by Stanford law professor Hank Greely, JD. In that talk, Greely noted science's steady advances in the genetic analysis of living embryos; the production of gametes (egg and sperm cells) from other easily accessed cell types; the matching of genetic variations to not only disease predispositions but also behavioral and physiognomic traits; and gene therapy, which could in theory modify those characteristics in gametes. Greely followed up with a stark prediction: Within the next 50 years or so, the majority of babies in developed countries will be spawned in IVF clinics.

As I wrote then, quite apart from some cautionary arguments regarding the ethics of such interventions, there were some strictly scientific grounds for skepticism. This report of a recent meta-analysis of IVF's effects, which concludes that babies conceived this way are at increased risk of having birth defects, reinforces those concerns:

Zhibin Hu at Nanjing Medical University and colleagues collected the results of 46 studies that compared the number of birth defects among children conceived using an IVF technique to children conceived normally. For more than 124,000 children born through IVF or using [an associated technique] in which a single sperm is injected directly into the egg, the risk of having a birth defect was 37 percent higher than that of the other children, they found.

This is by no means proof that IVF is, in itself, a dangerous procedure. It may merely be that the people who tend to use IVF are already more likely to have children with birth defects.

Still, the could be another flashing yellow light for birthing technocracy. The medical trade-offs of IVF and related technologies are such, and likely to remain such for a long time, that people without fertility problems per se will likely opt to go the old-fashioned route rather than high-tech option. A prominent exception: people who are carriers for a single-gene disorder they don't want transmitted to their kids.

Previously: The end of sex?, Sex without babies, and vice versa: Stanford panel explores issues surrounding reproductive technologies, and Stanford's IVF research on Time's top ten list

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