Let's not forget the teaching, offered in many a book on Catholic marriage and sex, that a man's organs are *outside* his body, which means he belongs in the outside world of ideas, politics, business, etc. And the woman's are on the inside, which means she's an "inside" person uniquely suited to home, husband, and children. 

Of course, a man made up this twaddle. 

You might as well base life on innie and outie belly buttons.