Why did they need a study to learn this?
My stepdaughter was in the Army National Guard. She married just before her unit shipped out for Kuwait. She came home a couple months later. Seems she got herself pregnant. At 5’1” she wasn’t much of an imposing figure anyway.
I used to coach youth soccer for all ages; and co-ed when the kids were younger. By the time the kids were ten-years-old the boys were already bigger, stronger, faster and “engaged!”
Even a person with a two-digit IQ recognizes that girls and boys—men and women are different physically and emotionally. It just beez that way!