Look at xkcd cartoons. Sometimes the focus of his cartoon is a relationship between a man and a woman - the stick-figure with longer hair is the female, or sometimes a stick-figure is given a beard to denote maleness. The sexes of his figures are central to these cartoons.
Most of the time though, his cartoons are just aboput two physicists, or a doctor and a patient, or whoever. Sometimes he might make a doctor (stick-figure with white coat and clipboard) female (plus long hair) even though it doesn't affect the joke.
So, I guess I'm comparing pro-nouns with cartoon pony tails....
To cite the man himself:
"The role of gender in society is the most complicated thing I’ve ever spent a lot of time learning about, and I’ve spent a lot of time learning about quantum mechanics."