I recently engaged in a conversation with several family members at once about gay marriage. I knew going into it that I would be a lone wolf, but I presented an argument which I think most people would agree with--even if they are against gay marriage. Basically the argument goes like this: All arguments against gay marriage seem to be rooted in religious beliefs; therefore, from a legal standpoint, denying gay marriage to those who do not share your religious beliefs is an unjustified moral imposition, which is both immoral and a violation of the establishment clause in the First Amendment. In other words, you have no right to deny someone else something based solely on your religion. I also gave a few examples of moral impositions, like Muslim anti-blasphemy laws being extended to non-Muslims and resulting in murder. I think most moral, thinking people will acknowledge the strength of this argument.
By this point in the conversation, at least one person was willing to see my point, and he and I pretty much agree on the moral implications of pushing religious beliefs onto other people. However, he did make one point which I don't feel I addressed very well at the time, and I wish to do so here. He said, "Is it OK for a society to want to promote a particular ideal?" My response was simply: "Yes." But having considered it more, I would qualify it a little. In order for a society to promote one ideal over another, which would grant privileges to one group and deny them to another group (i.e. heterosexual marriage vs gay marriage), they would first need to demonstrate that heterosexual marriage is better than alternatives, or that the alternatives are harmful to society. If they could do this, then it would venture out of the realm of a imposing religious views on to other people, and could then have a legal basis. But this has not yet happened! Therefore, in the specific case of gay marriage, I would have to tell him that it does not qualify, because the only reasons for such an ideal are religious. Besides, lots of religious people are OK with gay marriage--even Mormons!
I read a recommended article concerning the Mormon Church's views on gay marriage, and at one point they cite a sociologist, David Popenoe, who claims that homosexual homes are detrimental to the development of children. He justifies this claim by describing gender roles:
"The complementarity of male and female parenting styles is striking and of enormous importance to a child’s overall development. It is sometimes said that fathers express more concern for the child’s longer-term development, while mothers focus on the child’s immediate well-being (which, of course, in its own way has everything to do with a child’s long-term well-being). What is clear is that children have dual needs that must be met: one for independence and the other for relatedness, one for challenge and the other for support."
This is not a new argument, but it is still prevalent within conservative circles, so it should be addressed. Notice that at no point does he explain why gender roles are important, or how they actually benefit the children. He simply asserts it. He does not address the contrary claim that these roles (long-term and short-term needs) can be met through a homosexual couple. Why is it necessary for those needs to be met only by a man and a woman, respectively? Can the woman in a heterosexual couple be the bread-winner and the man stay at home? If so, why not two women, or two men? I know it is very difficult to study these things and it is one of the challenges social scientists face, as it is challenging to isolate variables in a social context. But it is important because failure to do so leaves a lot of room for personal views and biases to seep into the studies.
When you look at what every major psychological association in the USA says about homosexuality (i.e. the American Psychological Association), the idea that heterosexual couples are better for children than homosexual couples seems to be questionable. I have touched on this before, so I won't go into detail. But the gist is that homosexuality does not cause dysfunction in the individual, and homosexuals can lead normal, happy and healthy lives. How can this be if some sociologists say that gay couples are harmful to children? This is a major conflict between scientific fields. The psychological research is well founded, and seems to coincide with my own experience with gays, while the sociological evidence being presented against gay marriage from a few individuals seems to rely almost entirely on correlation (which is not causation). So, I see no reason aside from religious convictions to think gay marriage is harmful. Therefore, I still hold that denying gays the right to marry is a moral imposition.
Here are a few clips from the Atheist Experience concerning Gay Marriage: