But I can guarantee you that those differences are, like differences associated with skin color, far less than the differences between individuals in the same group.
I always chuckle when people trot that one out. Did you know it's equally true for the differences between dog breeds? Body size varies more within dog breeds than between them. Also intelligence. Somehow that doesn't stop dog breeds from being fairly different from each other. (Actually, somewhat more than human races from the genetic studies I've seen.)
As for the differences between guys and girls being taught not inborn...how many kids do you have? Parents get disabused of that sort of thinking pretty quickly.