Repro­duc­tive biol­o­gists have been working for decades to solve one of the great mys­teries of human fer­tility: why do women pro­duce all the eggs they will ever have while still in the womb, only to have most of those eggs die off before birth, and many more before the woman reaches puberty?

Jonathan Tilly, chair of the biology depart­ment at North­eastern Uni­ver­sity in Boston, was among those drawn to studying this enduring puzzle. But what he found instead was evi­dence of a fun­da­mental flaw in the basic tenets that govern our under­standing of the female repro­duc­tive system. If suc­cessful, his research could open the door to the most rad­ical advance­ment in infer­tility treat­ment since in vitro fer­til­iza­tion was invented nearly 40 years ago.

When Tilly exam­ined the ovaries of mice, he noticed that their eggs were dying much faster than the overall egg count would sug­gest. The mice appeared to be pro­ducing new eggs, and were doing so by a process that no one really understood.

Tilly’s team began researching the role that stem cells play in the process. Chi­nese researchers later iden­ti­fied a spe­cific type of stem cell located in the ovarian tissue.

Read the article at Maclean's →