sciencehabit (1205606) writes "Men typically produce working sperm as long as they live, but most textbooks say female mammals are born with all the egg cells, or oocytes, they will ever have. Since 2004, however, reproductive biologist Jonathan Tilly of Massachusetts General Hospital in Boston has challenged that conventional wisdom, arguing that in mice—and perhaps also in humans—there must be an ongoing source of new eggs. Today, Tilly and his colleagues report isolating rare cells in ovarian tissue from adult women that can grow in lab dishes and form immature oocytes. The potential egg stem cells could help scientists devise new ways to help rescue the fertility of women who have to undergo cancer treatments or who suffer from premature menopause."
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