^ Acsenray
You asked for a rational argument against homosexual “marriage,” so here one is. Whether you like it or recognize any part of it, I can’t say.
The first problem when addressing something as basic as this is to understand the true nature and purpose of the object in question. What is the true nature and purpose of marriage? Is it for the individuals or for society? If it’s simply for the individuals, then society has no reason to distinguish between whoever wants to get married. If it’s for the benefit of society, then the larger society has both an interest and a right in defining the institution. On the other hand, if it is basically for the benefit of the individuals, then society has no reason to specially privilege the state of marriage. Since it is privileged (both practically and philosophically), it appears to be for the larger society than just the two individuals.
In trying to understand the purpose of the institution, we might choose to look at an ideal case, what most people believe it should be, even if it doesn’t always achieve it. What characteristics do an ideal (in the platonic sense) marriage have? First, it’s enduring, permanent. Even though we’re aware that some marriages end in divorce, very few people get married expecting or intending to get divorced. We want it to be for a lifetime, even if we fail to achieve it. Second, it carries an obligation of sexual fidelity. Again, some people don’t follow this and don’t consider it important, but on the whole, this is one of the expectations. When people fail to live up to it, we, as a society, disapprove. Third, it generally produces offspring. Yes, either by choice or by unfortunate circumstance, some marriages don’t, but in the normal course of events, a married couple eventually has children.
So, we have a permanent union implying fidelity and some degree of stability that usually produces children. What purpose does this serve for society? It looks like a good situation for raising children. Stability and trust that these people will continue to be there sound like a great thing for kids. And (with certain obvious exceptions) being raised by biological parents is generally the best environment for children. These people have a clear, built-in predisposition to take excellent care of the children. In this context, sexual fidelity serves two purposes: One, it ensures that children are being raised by their parents. Two, it offers another assurance of stability. Developing a new romantic relationship is a chaotic process. (That’s not to say bad, but it’s not exactly stable either.) Breaking off a romantic relationship is even more so. Keeping these things to a minimum when there are already children involved seems like a good idea.
If we want to continue having society, then we have to have children. If we want to have a society worth living in, then we should take great care with how they are raised. Another societal benefit to marriage as I’ve described it is that it gives the members of a community a powerful interest in a strong, stable society. If a couple is thinking about the world their children will grow up in, they want to make it safe and enduring.
So does my argument invalidate childless marriages? Not necessarily. If they follow most of the other characteristics I’ve described above, they still serve to support and encourage the main purpose of the institution.
How does all of this apply to homosexual “marriage”? Obviously, the couple can’t have biological children. At best, they will be one person’s step-children. Although the numbers are still small, step-children are statistically more prone to abuse and other problems. Also (between men at least), there’s a lesser expectation of sexual fidelity in a homosexual “marriage” than a normal one. No matter how carefully infidelity is managed, it can create confusing and volatile situations. Also, even with children, the members of such a marriage don’t have the same genetically predisposed interest in a stable society.
From this standpoint, what benefit does society gain from privileging homosexual unions? Other than a vague sense of fairness, none.
Yes, I am aware that not everybody agrees with the understanding of marriage I’ve laid out. I know I’m not going to convince everybody. I was just answering the challenge as issued. I have other reasons, too, but these come from sources that my critics probably won’t recognize. I’ve tried to create a logical, secular argument here.