Question of Values for the Presidential Election

Why should family values be part of the campaign for the president? First of all I have never heard what is meant by family values. They probably differ from family to family and certainly from ethnic group to ethnic group. Why would any president want to get involved with how each family in the U.S. should act? Any kind of government involment with families really should not be allowed. I don't believe the constitution wanted our government to set laws on what values families must adhere to.