Single parent homes have family values, too. Just because someone is a single parent doesn't mean that they don't have family values and do not teach those family values to their children.
The importance of marraige is best left to the family. That is not something that a school system should be teaching, as it depends on the individual as to what importance they attach to it. It is a moral area, and schools are not in the business of teaching morality, nor should they be.
