Jennifer Finney Boylan of Maine teaches college English and has a remarkable op-ed piece in the New York Times making a fine point about same-sex marriage that has been mostly overlooked: it's been around - legally - for years.
Ms. Boylan was male when she married Deirdre, a woman, in 1988. They have remained married. They are both now women. In most states, that is. I definitely encourage you to read her entire contribution. It points out the absurdity of our nation's legal approach to gender. I laughed out loud while reading this section in which a lawyer handling the case of a transgendered Texan is quoted.
Taking this situation to its logical conclusion, Mrs. Littleton, while in San Antonio, Tex., is a male and has a void marriage; as she travels to Houston, Tex., and enters federal property, she is female and a widow; upon traveling to Kentucky she is female and a widow; but, upon entering Ohio, she is once again male and prohibited from marriage; entering Connecticut, she is again female and may marry; if her travel takes her north to Vermont, she is male and may marry a female; if instead she travels south to New Jersey, she may marry a male."