A line (like a groove or a seam) in the body where two halves developed before birth and fused together. The line along the underside of a penis that runs from the tip of the penis to the anus is called the penile raphe (along the penis) or the scrotal raphe (along the scrotum). This raphe reminds us that before birth, male and female genitals start out looking the same. In most male genitals, the two sides fuse together, leaving a line down the middle.