Some people are more prone to getting bitten by mosquitos than others, and a new study reveals genetics may play a big part.

Many studies have shown that mosquitos are attracted to certain body odors. What causes the differences in smell isn’t clear, though it was thought to have been diet related. A 2005 study revealed that body odor is somewhat genetic by comparing the scents of identical twins vs. pairs of non-identical twins.

To test whether mosquitos favored people with scents that were genetically caused, researchers tested 18 pairs of identical twins and 19 pairs of non-identical twins. They found that mosquitos tended to bite the identical twins’ respective arms at equal rates, while the mosquitos tended to favor one non-identical twin over the other. This is to suggest that attractiveness to mosquitos could be dependent upon genetics - a discovery that could offer insight into reducing the transmition of deadly diseases like malaria and dengue fever which mosquitoes are responsible for spreading.