As much as one 12-ounce bottle of beer can make you more attractive...to mosquitoes.

The experts say drinking increases the amount of ethanol excreted in sweat and it increases body temperature, but that's not exactly what attracts the pests.
Mosquitoes can smell lactic acid and other things in sweat and go for the higher temperature bodies.  Beer contributes.
Oh, and mosquitoes love pregnant women. Pregnant women get mosquito bites at about twice the rate of the general population.  In other words, mosquitoes love pregnant women even more than they like beer drinkers.
If you really want to trick the mosquitoes and keep them away, you're supposed to wear colors that stand out, like black, dark blue and red.  The bugs use eyesight to find us, and they see those better because they are colors contrary to nature.  If you wear plant-colored green and you've had a beer, look out!  You better have bug spray nearby.
The good news is, it's too hot to drink beer outside right now.  So maybe we're safe for awhile.