According to a 2004 study trying to link blood type to mosquito bites, a person’s blood type does indeed have an impact on these pesky insects.  For the vast majority of humans, our blood type is expressed through a chemical on our skin – not so coincidentally where most mosquitos land when they are looking for blood.  This study found that those with Type O blood are twice as attractive to mosquitos than people with Type A, and Type B blood holders are somewhere in between.  Other genetic factors also play into why some of us seem more attractive to mosquitos than others.  Unfortunately we have no control over this and, because mosquitos are attracted to blood type, you may be more or less predisposed to perpetually swatting at these insects on warm summer nights.