I've always said men are judged by what they don't do - he doesn't drink, do drugs, gamble, run around with other women, beat his wife. He is considered "good" simply for not doing bad things.
On the other hand, a woman's "goodness" depends on what she does and she has to do a lot - be a good wife and mother, keep a clean house, be a good cook in the kitchen and a good lover in the bedroom.
We have to be perfect and they only have to be better than the worst guy around.