The key argument of the New York Appeals Court is that it is not prima facie irrational to keep civil marriage exclusively for straights because the consequences of their irresponsibility extend to a third party, children. Civil marriage, in other words, is an incentive to behave better for the sake of kids. But what of civil marriages without kids? The "rational" standard is a very low one, of course. And the best case to be made is that because it's just easier to have kids accidentally in a straight relationship, then straights need the incentive more than gays. But what of those straight couples who are past menopause or sterilized? In New Jersey, for example, there's a pending court case that rests in part on this distinction. A reader explains:
In New Jersey, we have a 'domestic partnership' rule that allows two people of either the same sex, or of opposite sex over age 62, to enter into domestic partnership together. The DP provides some but not most of the rights of marriage. Presumably, an opposite sex couple over age 62 is allowed to enter into a DP because of this same issue articulated in the NY ruling like gay couples, heterosexual couples over age 62 are unable to produce any unintended offspring.
However, in New Jersey, an opposite sex couple over age 62 can also enter into a marriage. There is nothing in NJ law that prevents opposite sex couples over age 62 from getting married, as there is for gay people. So the NY reasoning would fail in NJ, because the logic of the NJ legislature has not been consistent in regards to children: either opposite sex couples over 62 and gay couples should only be able to enter into a DP, or both sets of couples should be able to either enter into marriage or a DP. Since children are not an issue in either case, the only reason to not allow gay people to marry but allow people over 62 to marry would be irrational discrimination against gay people.
Then there's the question of gay couples with children. It seems to me that if children are the standard, then civil marriage should rationally apply only to those with kids, gay or straight, and civil unions should apply to everyone else. Everyone gets a civil union license at first (unless they already have kids) and can upgrade to a civil marriage license after and only after they have reproduced or adopted. That's the truly rational policy from the NY decision.
As for Georgia, it's important to note that the court has ruled that gay couples are not only barred from civil marriage, they are barred from any legal protections whatever. Georgia wants its gays like it once wanted its blacks: segregated from integration into "normal" families, even if they have been born into them. And, yes, many thought that was rational for a very long time as well.
(My anthology on the arguments - legal, moral, historical, religious and constitutional - for and against marriage rights for gay couples can be found here.)