It may be a borderline-offensive schoolyard taunt, but "throws like a girl" has an element of truth. Studies suggest that girls often don't throw as well as boys. (Boys v. girls is a little diminutive, but it's an important distinction; we'll get to that.) In fact, the "throwing gap," as it's called, is one of the biggest differences between the genders. It's not just the largest gap in physical activities--although it's the largest gap in that field--it's possibly the most salient gap. Period.