Progress toward making “artificial gametes” has been accelerating. In Japan, mice were born from eggs scientists had manufactured in a dish from a tail cell. Chinese scientists later claimed they had determined the exact sequence of molecular signals required to make mouse sperm. So far, the exact biochemical formula for prompting a stem cell to mature into functional human eggs or sperm remains out of reach. No human skin cell has been turned into a bona fide human reproductive cell. But many scientists believe it’s only a matter of time—maybe only a year or two—before they get the right recipe. Recent advances have been “absolutely clear, and breathtaking” says George Daley, a stem-cell biologist who recently became dean of Harvard’s medical school.
As control over the fundamental units of reproduction advances, the work is drawing the attention of entrepreneurs, legal experts, bioethicists, and specialists in in vitro fertilization. Some believe that artificial gametes could be the biggest leap forward since IVF itself was first tried, in 1977. Many millions of people can’t reproduce, whether because of cancer, accidents, age, or genetics. “You’d be saying that if you have skin, which you do if you are even alive, then you can have sperm,” says B.D.
The technology could carry socially disruptive consequences. Women might have children regardless of age. Just grab some skin and poof, young eggs. And if eggs and sperm can be produced in the lab, why not also make embryos by the dozens and test them to pick those with the least disease risk or the best chance of a high IQ? Henry Greely, a member of Stanford University’s law faculty and one of the most influential bioethical thinkers in the U.S., finds that scenario likely. Last year, in a book titled The End of Sex, he predicted half of couples would stop reproducing naturally by 2040, instead relying on synthetic reproduction using skin or blood as a starting point.