Even when there was education, in most countries boys were taught differently from girls, and separately from girls, in a method called segregation. Long ago, most schools were run by religious denominations. That is because clerics were once almost the only people who were literate, meaning that they were able to read. Today, most countries have schools which accept both boys and girls. Despite this, some places still do have schools for girls. This is because some believe that girls do better in single-sex schools.