One problem with same sex marriage is that it normalizes a clearly deviant behavior. Being attracted to members of the same sex instead of the opposite sex is obviously a pretty severe mental disorder IMO. Normalizing this requires that homosexuality be treated as the equivalent of heterosexuality in schools, language, TV, etc. It therefore promotes this deviancy which does not produce children (something society has an interest in). I do not agree that the present marriage law is unfair to gays. If a gay man wants to marry a woman he has the same right as a straight man.
So do "civil unions." And this is exactly what Prager is advocating for.