Surveys show that women are more likely to be vegetarians than men. Some think that this is because women are more caring and have more empathy. The truth is that there are evolutionary reasons behind women's food preferences.
This paper(pdf) explains the idea. Meat has a higer risk of pathogen ingestion than plant food. In order to prepare for a possible pregnancy, women consume less meat in the luteal phase of their menstrual cycle. (The luteal phase begins right after the peak of ovulation.)
The paper goes on to say that since women consume less meat during this time (roughly 14 days out of each menstrual cycle), that they eat less meat than men overall. This also shows why vegetariansim isn't that big of a jump for women. If their body is not keen on meat for half of each month, then it's not that much of a change to just remove meat completely from their diet. This is not to say women should not consume meat, because it is an essential part of any diet.
