WASHINGTON - The female hormone estrogen can bend the gender of male fish that live in bodies of water contaminated with the residue of birth-control pills, a new study indicates.
For three years, Canadian scientists have put birth-control pills into a remote Ontario lake to measure this impact. The results: All male fish in the lake - from tiny tadpoles to large trout - were "feminized," meaning they had egg proteins growing abnormally in their bodies.
The experiment was intended to match the impact that the female hormone estrogen may be having on many American bodies of water, as city sewage systems empty waste into them that is contaminated with residue from birth-control pills.
One-third of male Pearl Dace minnows grew eggs in their testes. The entire population of the common Fathead minnow, once numbering in the several thousands, crashed to near zero because the hormone-stoked fish couldn't reproduce.
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WASHINGTON - The female hormone estrogen can bend the gender of male fish that live in bodies of water contaminated with the residue of birth-control pills, a new study indicates.
For three years, Canadian scientists have put birth-control pills into a remote Ontario lake to measure this impact. The results: All male fish in the lake - from tiny tadpoles to large trout - were "feminized," meaning they had egg proteins growing abnormally in their bodies.
The experiment was intended to match the impact that the female hormone estrogen may be having on many American bodies of water, as city sewage systems empty waste into them that is contaminated with residue from birth-control pills.
One-third of male Pearl Dace minnows grew eggs in their testes. The entire population of the common Fathead minnow, once numbering in the several thousands, crashed to near zero because the hormone-stoked fish couldn't reproduce.