Much of the debate around same-sex marriage has been biased towards the religious merits and condemnations of it, which I have refuted elsewhere. I think we should instead look at it from a perspective of fairness.
One’s sexuality is something one has little choice over. Sexual orientation – whether one is sexually attracted to men, women or both – is only one part of sexuality. It makes no differences whether this is something we are born as or become through the environment, it is something we on the whole can’t control.
If one can’t choose whether one is sexually attracted to men and women, is is fair to deny one the right to marry, simply because one doesn’t love someone of the opposite sex? Why should someone be denied the right to get married – the ultimate form of union – simply because they are designed to love people of the same sex as them, whether they want to or not.
It is discrimination, whether or not it is illegal, to deny someone a benefit that other people in society are entitled, simply because a physical or mental difference exists between them that make it difficult to access that benefit on the same terms as others.
In the social model of disability one is not disabled unless others are not accommodating one’s disabilities. Equally with marriage, society is disabling same-sex couples by not accepting that they have differences that would make them unable to access the same opportunities as people without their characteristics.