AUSTRALIA – Heterosexual men with sluggish sperm can now look to science to help them medically justify their enjoyment of hardcore pornography. A recent study has shown that, along with the more traditional responses associated with the viewing of explicit images of men and women together comes an unexpected bonus: it can increase the quality of sperm produced by the viewer. The same can not, however, be said of material featuring only women, regardless of whether they are engaged in solo or partnered activities.

Evolutionary biologist, Professor Leigh Simmons for the University of Western Australia, says the cause is something called “sperm competition,” which results when male animals perceive their chance of impregnating available, fertile females to be at risk due to competition — and the quality or quantity of their semen increases.

According to Simmons, merely looking at a photo of another man in the act of intercourse is enough inspiration to cause the watcher’s sperm levels to change. As the professor explains it, “human males viewing images depicting sperm competition had a higher percentage of motile sperm in their ejaculates.”

Interestingly enough, Simmons’ research shows that when heterosexual men can choose between erotic images depicting multiple people, they prefer to add men to the equation. When 52 straight men between the ages of 18 and 35 were shown photos on two different days, the men who saw photos depicting two men with one woman produced not only produced more sperm, but also more efficient swimmers than those who viewed images of three women. “It seems that men like to see other men in these images,” Simmons observed.

Simmons cautions that more study is needed before definitive conclusions can be drawn and that other lifestyle factors must be taken into account when interpreting the data.