by Jason Stotts
Not everyone knows this, but all fetuses start out as more or less female until it is about 7 weeks old or so. At that point, sex hormones cause the proto-female sex organs to close and begin to build the penis.
In the picture below, A and B are before sex differentiation. C and E are of a fetus that develops into a male and D and F are of a fetus that develops into a female. The line where the labia and related structures fuse together to form the scrotum and the penis is called a raphe and looks like a scar running from the anal opening to the glans (head) of the penis. When it is on the penis, it is called the “penile raphe” and all men have them. All men: Every. Last. One.
So, if you’re a man and you’ve spent years thinking you have a strange scar on your penis, think again. It’s just where your labia fused together to make your man parts.