You’ve probably already noticed that the penis and the labia majora have a distinctly darker shade than your legs or belly, for example. Unless you’ve just come back from a sunbathing session in a swimsuit, your genitals are generally the most tanned area of your body. Yet it’s the one you expose the least to the sun. So, why is sex darker than the rest of the body?
Everyone has asked themselves this existential question at some point. The website Slate answers it in an article.
Why sex is darker than the rest of the body
During puberty, the increased production of hormones, testosterone in men and oestrogen in women, causes a multitude of changes in our body. In particular, an increase in the sensitivity of melanocytes, the cells that produce melanin, the pigment responsible for the dark colour of skin or hair.
Among other things, these hormones activate the melanocytes present in the genitals, which darkens them. The nipples also undergo a similar change in colour.
Similarly, pregnancy also causes hormonal fluctuations, which can darken the nipples and draw a vertical line between the navel and the pubis.
Friction caused by clothing and hair removal can also contribute to darkening the area around the genitals. To protect itself from friction, the epidermis thickens naturally, and thus becomes darker. This phenomenon is particularly noticeable in athletes, whose genital areas and inner thighs are subject to constant friction when they run or jump.
However, while having a penis or labia majora darker than the rest of the body is completely normal, certain changes in skin colour should raise concern about a potential serious pathology. Among other things, sudden darkening of the groin, armpits, or neck can be a symptom of diabetes, or acanthosis nigricans, a rare skin condition that can be linked to certain cancers, obesity, or a hormonal issue.
Or perhaps you have tried perineum tanning, who knows? (For the sake of your genitals, please tell me no :-) )
