An eggsample of why it is hard to prove a negative
Earlier this year, a paper claimed to have found cells, called ovarian stem cells, in the adult ovaries of both mice and humans. These cells could apparently be grown in large numbers in the lab and could retain the ability to give rise to eggs. A new study finds no evidence for the existence of germline progenitors able to produce eggs in postnatal ovaries. Is a lack of evidence sufficient to win the argument?...