Actually, it does. Govt. has a role in keeping society stable. The foundation for doing that is the family with a father and mother. Therefore the govt. should promote marriage between mother and father. Since homosexuals can't have children they have no reason for marriage (other than to try and normalize their deviant behavour).
Actually, it doesn't.
The role of government in a free society is to defend rights. Not to keep things stable.
Stablity is another term for stagnation. You might like things stable (living to 53 yrs old on average and owning slaves) , but I don't.
PS........Please see the Declaration of Independence for confirmation of the rightful role of government in the American expeience.