Scientists uncover how some fish can change sex as adults

NEW YORK (AP) — New Zealand researchers are offering the first detailed view of the molecular machinery that allows some fish to change their sex.

Roughly 500 types of fish can switch between male and female as adults when circumstances call for it.

The study published Wednesday examined a tropical reef fish that can change from female to male. The scientists found stress was likely key to triggering the switch. They say that stress caused genes for the animals’ initial sex to turn off while genes for the new sex turned on. The researchers say the process requires an entire reprogramming of the fish’s genetic information.

The change is fast. It takes only minutes to a few hours for the female’s behavior to change. And after eight to 10 days, she transitions to male.