If you have one or have inspected one for long enough, you may have wondered what that seam-like structure of thicker skin is that runs from your penis, down through the center of your scrotum to your anus.
“In adults and children, the penile and scrotal raphe vary in shape and thickness between individuals and the anomalies include pearly, pigmented, prominent, or wide raphe,” a study which examined development of the raphe in fetuses explains.
Even if you haven’t vaguely wondered that, we’re going to tell you anyway: it is called a perineal raphe, and it formed while you were about seven weeks old in the womb. Before seven weeks of the mother’s pregnancy, male and female fetuses look fairly similar in the genital area, each with a urogenital tubercle, urogenital swellings, and urogenital folds.
After around seven weeks, the testicles in male fetuses that are progressing typically will produce testosterone.
“The testosterone causes the urogenital swellings to swell, come together in the middle, and fuse, forming the scrotum and the underside of the penis,” the Intersex Society of North America explains on their website, adding that unusual levels of hormones can result in intersex appearance.
“The line down the middle, called a ‘raphe’, is just a reminder of how all humans start out with a common female genital anatomy until 7 weeks after conception.”
The line is known as a penile raphe where it appears on the penis, and a scrotal raphe where it appears on the scrotum. The raphe is also present in females, extending from the anus to the labia majora, from the development of their genitals in the womb at around the same time.
So there you have it: that stitch is a relic from a time when your genitals were just distinguishing themselves in the womb, you have not been secretly stitched up while you were sleeping. Probably.
Source Link: What Is That "Seam" Running Along The Middle Of Your Ball Sack?