Raise your hand if you've ever felt personally victimized by a single, tiny mosquito. It's an unfair reality, but there exist people among us who have never been bitten by one of these evil, little bugs. Sadly, there is science that backs up mosquitos' purpose on this earth, so wiping them out isn't an option. But, we'd like to ask science: Can we at least know how mosquitoes determine who is bite-worthy and who is spared?Related: How Tattoos Are Helping Women Recover From Serious Health Issues The jury is still out on the exact reason, as it must be tough to get a mosquito to sit down and answer a few questions (they're too busy ruining picnics and trips to the lake). The overwhelming explanation is that it is, somehow, related to blood type. According to Elizabeth Tanzi, MD, "it’s typically type O blood that attracts them.” Apparently type O really is the universal donor.Related: Where On Your Body You're More Prone To Getting Skin Cancer The one overwhelming truth to remember about mosquito bites is to avoid scratching them at all costs. As Dr. Tanzi explains, "by scratching, you cause more trauma to the area, which causes more swelling."Related: 8 Ways You Could Be Damaging Your Eyes At The Beach