Frosstbyte

I can't.

And I couldn't care less. If someone wants to screw and marry his sister or his mom or his fifth cousin, that's not my business. If they want the rights and responsibilities that I gain from and owe to my wife, I'm happy for them to have it. All I ask is informed consent. I mean, I think it's strange. I don't want to do it, but a cursory search of pornography will show you that incest fantasies are downright common.

The "child" line is flexible and arbitrary, as you said, but there's something inherently different about children and their ability to make sexual decisions and adults, even if those adults make decisions you don't agree with. We call people legally children and legally adults based on when we as a society decide they can make informed decisions about their lives-which includes taking into account consequences and long term impacts. If some theoretical society decides that 9 year olds understand "sex" well enough to make decisions about sex, I guess that'd be strange.

But, I think that children, much more so than incest and polygamy, is a total red herring in the gay marriage discussion. The revulsion to pedophilia is much more common and much more extreme because so many more people recognize that it's scary and dangerous TO THE ABUSED CHILD. People don't worry about gay people being harmed by their relationships in the way you worry about a priest or a teacher or a random person abusing a kid, because it's a different concern. Likewise with adult, consensual incest and polygamy. Those relationships make people uncomfortable for, in part, historical reasons and social taboos, not because of a fear that someone is taking advantage of another who doesn't understand the consequences and long term impact of the situation.

Edit: After IL's post, you don't get to say "marriage is for the state" in a post like that. The reason the vast majority people are against gay marriage is religious. If Mormons don't want to marry gays in the Mormon church, that's one thing. I would defend their right to do that every time (though I still disagree with it).

It is an undeniable fact that the very effective campaign against Prop 8 was financed in no significant by the Mormon Church, not to deny gays the right to get married in their church, but to deny them legal rights as married couples. The fact is that churches and people thinking in the context of their church are making decisions that impact other people who are not part of their church. I'm not making a church/state argument, just that it's impossible to extricate the two, given how both individuals and church institutions react when same sex marriage is on the table. I cannot conceive of a legitimate reason that state marital privileges should not be extended to any consenting adults who wish to marry. All the examples people bring up have irrational "ew" connected to them, which means pretty much nothing to me. Governance should not be based on ew.