英语时差：鱼会变性？（上）

A human is born one sex or the other depending on the chromosomes inherited from the parents. Even a surgical sex change, can’t enable a man to produce eggs or a woman to produce sperm. But several kinds of fish not only can change sex, but do so as part of their normal reproductive cycles… In most sex-changing fish, nearly all the young are born female and as they grow up, some become male. In others, the change goes from male to female. Either way it goes, the sex change works with the lifestyle of that particular fish to produce the largest number of offspring. Fish that change from female to male–including parrot fish, sea bass, and groupers–usually live in groups of one male and several females.