Selects: Birthmarks: Probably Not the Mark of the Devil

“If you have a birthmark that looks like a bullet hole in your back, that means you were shot in the back in a past life.” That’s one of the more colorful explanations humans have cooked up for a phenomenon that remains surprisingly mysterious. In this episode of Stuff You Should Know, Josh Clark and Chuck Bryant wade into the world of birthmarks—what they are, what they aren’t, and why we still don’t fully understand where most of them come from.

The Two Big Categories: Vascular and Pigmented

Birthmarks are broadly divided into two families. Vascular birthmarks are reddish or purplish because they stem from clusters of overdeveloped blood vessels near the skin’s surface. Pigmented birthmarks are brown, blue, or black, caused by an aggregation of melanin—the same pigment that gives skin its color. The hosts are careful to note that, technically, a true birthmark must be present at birth, though some common types (like strawberry hemangiomas) often appear a few weeks later and still get lumped into the category.

Vascular Birthmarks: Angel Kisses, Stork Bites, and Port Wine Stains

The most common vascular birthmarks are macular stains—flat, pinkish patches often called “angel kisses” (on the forehead) or “stork bites” (on the back of the neck). These usually fade by age two or three and require no treatment.