Crows feet are fine lines and wrinkles radiating from the eyes. For the most part they're caused by sun exposure, but smoking can make them worse (good thing i don't smoke). Years and years of smiling and squinting can also play a part in how they're formed (dang, perhaps i shouldn't smile so much).
So why the double standard? From what I can tell, I think the majority of people have the same feeling about them. When a man has crows feet, I'm not sure he even notices he has them, and if he does he's not going to openly complain about them. But when a woman begins to have them, it's buy the most expensive eye cream you can find! Seriously, if you google 'crows feet' the number one result is "The Doctors Book of Home Remedies for Womens Crows Feet." The woman's perception of a man with crows feet is practically the polar opposite of a man's thoughts of a woman with them. From the womans point of view, crows feet on a man can be considered handsome, adorable, or endearing even. Not so much for the woman, who gets labeled as old, and with wrinkles. (Of course I think as a woman we are all guilty of presenting this feeling upon each other as well.) But with that, they are seen exactly as what they are on women, wrinkles. But on men, it's like they are aging well, and instead of cute, they get labeled handsome. I'd have to say... that is a bit unfair, or maybe this is just all my perception. Then again, i guess women win the long hair competition. since Women w/ long hair = cute, Men w/long hair = so not cute.
Here I have two exhibits.
Exhibit B. Kyra Sedgwick, obviously if this were a magazine photo those crows feet would be photoshopped/airbrushed out in no time flat.