My theory on why we get certain sized boobs

 What if a women died and her boobs would fly away like a boob essence and it went to a girl who didn't have any and that boob essence determined the new girls boob size so you would have the essence of a random womens boob size and from each person it goes to it grows a little and for the little girls who died young without boobs and that's why everyone's boob size it different sizes and for the people who had plastic surgery the person who gets their boob essence the boobs shrink. That's why we have different sizes :D.