Canadian research suggests that women are better equipped than men to fight off infection, such as cold and flu. A Canadian study indicates that the female hormone estrogen gives women's immune systems added bite at fighting off infection. The researchers believe women may have evolved a more robust immune system because of their key role in producing and nurturing young; in evolutionary terms it only takes one male to reproduce with lots of females, but females are much more important in terms of producing offspring.


I think I can put it more simply than this. Women fight off colds quicker than men because they have to. When a man has a cold he stops everything and makes small whimpering noises while lying on the sofa watching TV. No incentive to get better there! When a woman has a cold, in addition to her usual chores, she has the added task of blowing her nose.