Why extend marriage rights to the class of people who are infertile? I don't get why you're giving that class of people special privileges.
And do you really want to equate homosexuality and infertility, which for all intents and purposes is a medical disorder? Is that where you want this conversation to go? It's not where I want this conversation to go. My sexuality is not a medical disorder.
As I've argued at length in this thread and the comments I've linked therein, I don't think it's reasonable to consider that standard met here.