This article on equality has some good (and amusing) points:
Bear in mind we're talking the British version here, so it may not translate to gay marriage law in the States...
"The drafters have belatedly realised that, since there is no procreative act which defines homosexual behaviour, there can be no consummation, or non-consummation, and no adultery. These will not, therefore, be grounds for gay divorce. If your gay husband offers you no nookie, or if he avails himself of large amounts of nookie elsewhere (or both), he gives you no legal cause to divorce him.
So what they have ended up offering, strangely enough, is a law of marriage with no sexual element whatever. This has never happened before (although there have been plenty of sexless marriages). There is nothing in Mr Cameron’s new law to say that same-sex marriages must be between homosexuals. If I were a bachelor, I could marry a straight male friend just to get whatever tax advantages, travel deals and insurance discounts might be going. Incestuous marriage remains forbidden, but I don’t see why, in Mr Cameron’s vision of same-sex marriage, a mother could not marry her daughter or a sister her sister or a father his son. No sexual act is expected of them and even if – distressing thought – it did take place, it could have no genetic consequences. Why should such pairs not just agree that they fancy the married couple’s exemption from inheritance tax, and hurry down the aisle? How long before a same-sex, keep-it-in-the-family couple tries to make a fight of it, and wins a case against the British Government at the European Court of Human Rights (ECHR)? "
"If you stand back to look at how Equality works, you notice three things.
One is that it undermines freedom. It specialises in attacking ways of living which people have developed for themselves, often using the law and even the police to do so.
The second is that it undermines institutions. The bulwarks of a free society are not atomised individuals, but businesses, families, schools, clubs, churches, charities, sports teams – the Big Society we seem recently to have stopped hearing about. Equality is the government’s instrument for nationalising them.
The third is that Equality makes everyone (except lawyers and other activists) very unhappy. No one knows where she or he (you see!) stands, what law he might inadvertently be breaking, what “inappropriate” remark he might have made."
To quote Jerry Pournelle; "Free men are not equal, equal men are not free."