In contrast to some other active threads, I just found this article from Smithsonian Magazine:
http://blogs.smithsonianmag.com/science/2013/07/why-do-mosquitoes-bite-some-people-more-than-others/
To attract mosquitoes:
– Have Type O blood (bit twice as often as Type A)
– Exhale more Carbon Dioxide (generally larger people)
– Sweat a lot
– Have large amounts of a few kinds of bacteria on your skin (vs. a diverse population)
– "Just a single 12-ounce bottle of beer can make you more attractive – to the insects."
– Be pregnant (attract twice as many mosquitoes)
– Wear colors that stand out (black, dark blue, or red)
– Lack natural repellents (some people produce natural mosquito repellents)
– Have other genetic factors, "estimated to account for 85 percent of variability between people"
— Rex