Co-education
With secondary education, children go through the process of puberty, and there is no general agreement as to whether both sexes should be educated together. People make arguments both for and against the idea. At one extreme is the United States in which both sexes are usually educated together at all stages. At the other extreme are certain traditional societies in which girls do not get a secondary education at all. The tendency has been for more countries to move to co-education as the standard at every level of education. An exception would be the Islamic world, where girls are educated separately from boys or even not educated at all.