Penises come in many shapes and sizes, but most have one thing in common: a toadstool-like head known as the glans. Whether they’re short or long, thick or thin, circumcised or not, all penises have that distinctive look that makes you think of everyone’s favourite fungi. And while it may seem silly, there’s actually a good reason for our penis’ resemblance to a mushroom.
The glans is an important part of the penis that plays a role in sexual reproduction. The shape of the glans allows it to displace sperm from previous partners, increasing the chances that the partner’s sperm can fertilise an egg and create offspring. Several theories exist as to why the glans has this mushroom-like shape, including sperm competition and sexual selection.
According to State University of New York Professor Gordon Gallup, a leading theory is that the mushroom-shaped head evolved as a way to scoop out the semen of love rivals during sex. This would help prevent a male from being impregnated by sperm from multiple men, which could have led to genetic defects in offspring.
While this theory has less empirical evidence than other theories, it still provides an interesting explanation for why the glans is mushroom-shaped. It also offers a potential rationale for why some men have more of a phallic-shaped glans than others. Although, as a general rule, the shape of a man’s glans is determined by genes, there are some medical conditions that can cause the glans to be shaped differently than normal (like hypospadias and Peyronie’s disease). Penis size and shape are also mostly dictated by genes but can also be affected by dietary and lifestyle choices.