I find it difficult to disagree with the professor when you leave it in the context that she has it. Marriage has been reshaped over time. If gay marriage is another simple reshaping of marriage, then what is the precedent for preventing it?
But is that the only possible context? What about a different context? In this context, marriage serves to guard against the normal behavior of men. Without a legal binding and civil repercussions, men will be more likely to abandon the women with whom they have sex, and consequenlty abandon any children that result. But with marriage there is a legal binding and civil repurcussions if men skip town after sex. At the same time, if women restrict sex until marriage, then the only way that men can get sex is through marriage which binds them to provide for any possible children. In other words, the entire purpose of marriage is to bind children (the outcome of sex) to their fathers through an agreement with their mother. Marriage is the primary tool that protects against deadbeat dads being the societal norm.
In that context, marriage serves to protect and educate children. So how good of a job can same sex marriage do at this? Although same sex couples are not currently capable of reproducing, they can certainly acquire children through other means (e.g. adoption or sperm donation or egg donation + surrogacy). How good of a job will same sex parents do at protecting and educating their children?
One part of educating children is to provide them role models from which they learn appropriate life behaviors. In a same sex marriage, there is either no adult female figure or no adult male figure who lives with the children. Does this have a negative impact on children? The knee jerk reaction is to say that it does. But I think the answer is that it might not. If we assume that homosexuality is genetic (as most gay advocates seem to espouse) then if a lesbian couple has a lesbian daughter, they will be fully equipped to provide appropriate role models. The same thing is true if two gay men have a gay son.
Let's use some math to figure out how likely this scenario is: Take it for granted that there's a 50% chance of having a boy vs a girl. Also, assume that the 10% society is right, and that 10% of the people you encounter are gay. That would suggest that the genetic code that results in homosexuality is likely to occur 10% of the time.
This means that a gay couple will have a 10% chance of getting a gay child. And only half of the time, will that child be the same sex as they are. So they have a 5% chance of being able to provide an effective role model to that child. Meanwhile, a straight couple will have a 90% chance of having a straight child, and all of the time an adult role of the same sex will be part of the mix. So a straight couple will have a 90% chance of being able to provide an effective role model. In other words a straight couple is 18 times more likely to provide good role models than a gay couple.
Of course, that conclusion rests on an assumption that homosexuality is a genetic charateristic. What if it's not? What if homosexuality is not determined by genes, but influenced by the child's environment? In that case, we would expect that the child of a gay couple will be influenced towards homosexuality, and the child of a straight couple will be influenced towards heterosexuality. Anyone who is a parent knows that you can't always control every aspect of your child's environment. But if the 10% society is right, then roughly 10% of the time, a child will flip from the environment they were raised in. Which is to say that 90% of the time a gay couple will end up with a gay child, and 90% of the time a straight couple will end up with a straight child. In the straight couple's case, there will be an adult role model for that child 90% of the time. In the gay couple's case, there will be an adult role model for their child 45% of the time (i.e. when a lesbian couple has a daughter, but not when a lesbian couple has a son).
In this scenario, a straight couple is only twice as likely to provide the appropriate role model for their children in comparison to a gay couple. This is quite an improvement from the 18 fold difference if genetics are involved. Which leaves gay rights advocates with a Faustian bargain. Either:
- they cling to their long held belief that homosexuality is genetic AND they have to admit that they're way less likely to be able to provide an appropriate role model for children, or
- they improve their odds of being a good role model, but they have to admit that genetics doesn't play the role they think it does.