Conventional wisdom says a woman is born with a set number of eggs, which are gradually exhausted over time. But a new animal study threatens to turn that dogma on its ear. Harvard researchers have discovered that mouse ovaries apparently create new oocytes throughout the animal's reproductive years. Of course, these findings have to be confirmed and similar research has to prove it applies to humans. But, according to the American Society for Reproductive Medicine: "If we could tap the follicle reserve as a means to postpone ovarian failure, that could be the most significant advance in reproductive medicine since the advent of in vitro fertilization more than 25 years ago."
Johnson J, Canning J, Kaneko T et al. Germline stem cells and follicular renewal in the postnatal mammalian ovary. Nature, 2004; 428: 145-150.