I honestly don't know. I think it's weird. But usually the lighting is better in the bathroom than anywhere else, so that might be why. I don't like it 'cause I usually get distracted by the toilet in the background; sometimes, the lid is up. :/
What other room in the home is considered "private ",particularly if the pictures are of a personal nature. Most parents aren't down with the skin shots most girls are willing to send their friends, or to triple x Porn sites.