Mosquitoes find some people tastier than others. But a widespread notion is that women, to mosquitoes at least, are the sweeter sex, supposedly because estrogen is a strong attractant. In reality, gender does play a role, but not in the way most people think.
http://www.nytimes.com/2010/06/15/health/15real.html?src=twt&twt=nytimesscience