Did you ever hear that having sex standing up reduces the chance of pregnancy? Although almost one in five guys between the ages of 18 and 29 believes it, that’s about as right on as the one about the moon being made of green cheese. As in, completely fictional. Not true. Not even a little. Gravity’s got nothin’ on sperm—they can swim. So if you do it standing up, make sure it’s just for fun, not for birth control.