I believe it is a hygienic practice, and I have heard stories about men having to do it later in life. My spouse bailed on me when I was 6 months pregnant, I could not count on having a reliable man around to help me raise him and teach him about how to take care of himself down there, and I did not think it would be healthy to have his mom running after him to make sure he was doing it right (future therapy bills avoided.) He's fine with it, as an adult, I asked him if he had any contention with it. He does not and thinks it silly to make a big deal about it.