WINTER GARDEN, Fla. — In the gender-bending waters of Lake Apopka, alligators aren't quite male. They aren't quite female either. They may be both. Or neither.

This sexual confusion in the wild, discovered in this steamy Florida swamp last year, is so disturbing to scientists that they keep performing test after test on the scaly reptiles, trying to prove themselves wrong. But the more they look, the more evidence they find. In fact, hardly any young alligators with normal sexuality can be found in this vast lake on the suburban outskirts of Orlando.

Elsewhere around the world, the same astonishing phenomenon is turning up in a menagerie of fish, birds and other wild animals. Testosterone levels have plummeted in some males, while females are supercharged with estrogen. Both sexes sometimes are born with a penis and ovaries, and some males wind up so gender warped they try to produce eggs.

"Everything is really fouled up. It is indeed real, and it is scary," said Tim Gross, a University of Florida wildlife endocrinologist on the team that discovered the feminized alligators. "We didn't want to believe it, in all honesty."

This is no fluke of Mother Nature, no quirk of evolution. This is probably a legacy of pollution.

Wildlife scientists have uncovered persuasive evidence that artificial pesticides and industrial chemicals are infiltrating wombs and eggs, where they send false signals imitating or blocking hormones, which control sexuality. Although the parents are unharmed, their embryo's sexual development is disrupted, and some male offspring are left chemically castrated and females sterile.

The potential consequences, if unabated, are almost unthinkable.

If males aren't male and females aren't female, they cannot reproduce, and some outwardly healthy populations could be a generation away from extinction.

"Biologically, this is the most significant thing that could impair species and populations across the continent and across the globe," said Timothy Kubiak, chief of contaminant prevention and investigations at the U.S. Fish and Wildlife Service.

So far about 45 chemicals, many of them organochlorine pesticides widely used by farms and households to kill insects and weeds, have mimicked estrogen or inhibited testosterone in laboratory tests and in wild animals.