Over the years, there have been certain conventions that have become associated with the two most common genders, males and females.
When it comes to hair, women are generally taught from a young age how to look after their hair, including how to properly clean it, how to keep it shiny and neat, and more. Men, on the other hand, tend to only shampoo and condition their hair and not much more, and every now and again they will go get a haircut.