What does it mean so the player can change the genitalia thing.
You can't change a person's genitalia. If they have genitalia that you don't like, don't have sex with them.
On the top right there's a heart. When you click it you see the other characters. Each have a heart beside their avatar, that is "on" (red heart) by default. You can click the heart to turn it off, you won't see those peoples content.