From a design perspective, the crotch is just about the worst place you could put a penis and balls.
The primary way humans move is their legs; anything that could impede the movement of the legs is inefficient. A big, dangling 10 inch penis would constantly be hitting the legs, constantly getting in the way. It’s a design flaw.
The balls are even worse. Other than the eyes, they’re easily the worst weak spot on the body. And legs form a V-shape, literally channeling any upward kicks right toward the crotch.
Girls crotches are smooth and flat. They have no weak spot. There’s nothing hanging in the way of their legs. Panties and leotards fit tight and perfectly.
Girls have the better design, and that’s a fact.