My cousin had a SAHM and a preacher for a father. She went away to a very strict, conservative, gender segregated christian college and turned up pregnant. Shock! Like the Palin's, her family supported her in spite of their disappointment.
This is what many people, even conservatives, don’t understand. “Family values” DOESN’T mean controlling everything every member of your family does so that they don’t screw up. It means being there for them when they do screw up to help minimize the effect and get them back on their feet. This is exactly what Sarah did for her daughter.
Family values is about guiding your family toward the right path. That doesn’t mean they’ll take it.