Why is the penis mushroom-shaped?

MEN might spend a lot of time thinking about their penis size.

It might not have occurred to them contemplate why it’s shaped the way it is.

The ridge that separates the head of the penis from the shaft – resembling a mushroom – could’ve helped men scoop out the semen of love rivals, ensuring they impregnated their partner over a rival maleGetty – Contributor

It turns out, there’s a reason why penises have a mushroom-like ridge.

Professor Gordon Gallup, from the State University of New York, led a team of scientists to investigate the anatomy of the human penis and its use in 2003. They came up with some pretty interesting ways to test out why penises are mushroom shaped.

Way back when, experts believed the penis evolved to become a “tool,” with a ridge to remove the semen of love rivals.

The theory behind this is quite simple – basically, men wanted to ensure they are the one who carries on their lineage and wins out in pregnancy.

Professor Gallup’s team sought to look into this theory. They found the thrust of the penis – and the ridge that separates the head from the shaft – could actually help clear a woman’s vagina and reproductive system of a previous lover’s sperm.

This meant a new partner could remove any competition, and replace it with his own semen.

They tested their theory in the lab, with latex penises and model vaginas.

Mixing starch and water together, they found the ridge around the top of a man’s penis could scoop out more than 90 percent of the “semen” substitute, in just one thrust.

Professor Gallup explained: “We theorize that as a consequence of competition for paternity, human males evolved uniquely configured penises that function to displace semen from the vagina left by other males.

“Thus, the human penis may enable males to substitute their semen for the semen of their competitors.”

He said they found evidence that couples tend to have more energetic sex if the woman has been suspected of cheating, or if a couple has been apart.

It could, he said, be down to a subconscious desire to rid his partner of any trace of another man’s semen.

Professor Gallup’s colleague, Rebecca Burch added: “A longer penis would not only have been an advantage for leaving semen in a less accessible part of the vagina, but by filling and expanding the vagina it also would aid and abet the displacement of semen left by other males as a means of maximizing the likelihood of paternity,” in the study, published in the Journal of Evolutionary Psychology.

Getty People often wonder why the penis is mushroom-shaped[/caption]

The theory dates from centuries ago when women would have sex with a number of partners, to increase their chances of getting pregnant.

So, while that might be why the human penis evolved as it did, chances are it will be less important to men these days.