Do you use weed killers? Well, you may think twice after you hear about herbicide-doused male frogs that turn female. They don't just act female--mating with other male frogs (see photo)--they actually produce real eggs.
Atrazine, the common weed killer, can turn male frogs into females when the frogs are exposed at levels found in nature (levels that the US EPA says is safe for drinking water). In the photo at right, the frog on the bottom is a feminized male that is mating with the normal male on the top.
The feminized male frogs do more than just mate with normal males, they produce viable eggs.
So watch out for that weed killer guys, you may not like the results. And your partners may like the results even less than you do.