Male nipples have always been a source of cultural fascination (case in point: that unforgettable scene from Meet The Parents). But do they serve a physiological purpose? And if they don't, why are they still a thing?As part of its 12 Days of Evolution series , PBS Digital Studios took a deep dive into these questions. The new video explains that, unlike female nipples, which facilitate breastfeeding and can play an important role in nurturing babies, male nipples offer no kind of evolutionary advantage. (Spoiler alert: Ben Stiller was not able to milk Robert DeNiro in that aforementioned scene.)That being said, male nipples don't really present a disadvantage to human survival, either (unless you count the occasional locker room purple-nurple as a "disadvantage"). According to the video, it would be less evolutionarily efficient to phase nipples out of males only. In other words, evolution isn't always as selective as one might expect.The video also highlights instances in the evolution of other animals in which certain physical traits were repurposed, depending on the animals' needs (like penguins using their wings to swim). So now we're just patiently awaiting the day when male nipples become somehow useful for something. Only time will tell.Check out the full video below.