The main argument that the right wingers use these days to oppose marriage equality is "children deserve a mother and a father." This argument is specious and illogical and I am really tired of it. It makes no sense.
Do they think that gay people will stop raising children if they can't marry? Of course we won't. WE already have children and they aren't magically whisked away if we aren't married.
Do they think that gay people can't adopt or foster children if they can't marry? California's prop8 said nothing about children or adoption. No anti-marriage amendments touch this. Gay couples in California and many other states continue to provide loving homes for foster children and adopted children despite the bias against us. Banning marriages between gay people has nothing to do with adoption.
Do they think that gay people will stop having their own children if they can't marry? We already have biological children, from previous (straight) marriages, or by other means, such as surrogacy--all perfectly legal, and unaffected by marriage.
Do they think that gay people who want children and aren't allowed to marry, will turn straight? To which one answer is, would they want a gay man to marry their daughter for the sole sake of breeding?
Do they think that straight people will stop having children if gay people marry? Obviously the species is in no peril, since straights outnumber gays by 10:1 at least! And remember, nearly all gay kids had straight parents.
The fact is that by denying civil marriage to us, they willingly put our children at risk. Marriage between parents is good for kids. If they cared about children, they'd care about ALL children.
And the fact is that that civil marriage is not linked to childbearing, nor to adoption: they are completely separate issues.
Now, if you want to use that argument to try to forbid gay couples from adopting, that would be logical. Wrong, but logical. But as I've shown, it has no bearing on the question of whether two faithful and commited people who happen to be of the same sex, should be able to marry.