This whole thread is full of reasons but no one wants to listen to any of them. My reasoning is lacking so you're asking the wrong person. I'm not very good at debating. That's why I'm always quoting someone else that seems to fall in line with what I believe to be true.
The reasons I have gleaned thus far:
1. Homosexual/Lesbian relationships are wrong and should not be state-sanctioned.
--- Well, this one won't work for me. Its an argument based on a number of religious texts to which I do not ascribe.
2. State sanction of SSM will result in an undue burden on the financial structures of the state.
--- Scot C. Tryphal's arguments regarding this issue seem to the point. I do see how Social Security spousal benefits would be increased, and how insurance company premiums might be affected, but I don't think that these two items are sufficient to deny SSM. Again, if these are concerns, than discouraging heterosexual marriages would be a much easier way to control costs. Aren't there more of 'US' than 'THEM'?
3. State sanction of SSM will result in a cascade of changes to existing laws.
--- I am not sure if this is the case. As I noted previously, it seems that the sex of the spouses should not impact the laws regarding the benefits and liabilities of marriage. There are probably some old laws on the books that would be made instantly ridiculous. Oh, state laws regarding sodomy would definitely be affected. I don't see that as a bad thing.
4. State sanction of heterosexual marriage is necessary to ensure that the procreation and rearing of children is managed to the benefit of the state. Sanction of SSM is not necessary as children cannot result in an unplanned fashion.
--- Well, Zig and a variety of other people have been beating this one up. Regardless of children being planned or unplanned, if we know that families are being created and that the children must be attended to, it seems to me to be more effecient to bring into play the already existing laws rather than create a whole new body of law.
5. Children raised in homosexual/lesbian households are more likely to be gay or suffer emotionally or suffer in their maturation, etc.
--- From the study links posted by other folks, that doesn't seem to be the case. I don't think this reason stands.
6. Lots of paperwork will have to be changed to reflect both spouses being the same gender.
--- Yes, this is true.
7. Children will be conceived using 'unnatural' means.
--- As heterosexual couples are already using in vitro fertilization and sperm donation, I don't see how the use of these methods by same sex couples could be a problem.
OK, Hardenbergh - any others? What do you think about my analysis above (leaving out #1, we'll just agree to disagree on that).
By the way, I think I'm terrible at debate. I regularly wish I were half as eloquent and well-versed as a number of posters on this board. But practice is helping.