Why Don't More Animals Change Their Sex?
Most animals, like humans, have separate sexes — they are born, live out their lives and reproduce as one sex or the other. However, some animals live as one sex in part of their lifetime and then switch to the other sex, a phenomenon called sequential hermaphroditism.
Boys will be boys and girls will be girls, but will some boys become girls, and some girls become boys?
According to Kazanc?o?lu, "Reproductive behaviors such as parental care seem to disfavor sex change in some species. We are investigating whether general patterns like these may explain the rarity of hermaphroditism."