Transplant reroutes cells from sperm to eggs

Fish cells destined to become sperm can morph into eggs when transplanted into larvae, a new study shows.

Some fish species can switch from male to female either spontaneously or when treated with steroids. This knowledge led Goro Yoshizaki of the Tokyo University of Marine Science and Technology and his colleagues to wonder whether the gonads of male fish contain cells that might become either eggs or sperm.