Having a hard time pitching your tent, if you know what we mean?

A new study suggests your blood type may be the culprit.

Researchers from Turkey have discovered that men with type O blood are significantly less likely to have erectile dysfunction (ED) than those with type A, type B or type AB blood. Moreover, men in their study with type A and type B blood were about four times as likely to struggle with ED than type O dudes, while men with type AB blood had almost five times the risk.

Past studies have found that certain blood types – particularly AB – are associated with other health issues, including heart disease, higher cholesterol and blood clots.

Researchers say the same mechanism responsible for those health issues may be driving the connection between blood type and ED. Past studies have, in fact, demonstrated how problems with erections may occur three years before a man is diagnosed with heart disease. This is due to the fact that the arteries in the penis are far smaller than the arteries around the heart, meaning they’re more likely to show the effects from damage or build-up first.

Those with type A and type B blood also have higher levels of adhesion molecules in their blood, which can result in plaque build-up in the arteries. This can have an impact on blood flow, both to the heart and the penis, which can lead to higher risk of heart disease and ED.

It’s also a possibility that other genetic components of the A and B blood types could result in blood vessel damage, which can impede the biological processes required for getting an erection.

Researchers say more studies are needed to solidify the link between boners and blood types. In the meantime, feel free to blame your vital fluids for your not-so-stiffy.

h/t Men’s Health