"but it was not a logical impossibility that they marry, as it is with a man and a potted plant, or a man and another man"

It is not a logical impossibility for a man to marry a man. If it were, we wouldn't be having this discussion. Conflating same-sex marriage with the idea of 'marrying' an insentient, non-human object is a totally amateur-hour move. Until plants require immigration sponsorship and can inherit estates and consent to contracts and... well, you get the idea... you'll need a better argument.

Marriage is about protecting *families*, however those families are constructed - whether through plain old sexin', infertility treatments, adoption, blending of divorced families, or even (gasp!) donor gametes. And let's not forget married couples who are childless by choice -they get to be protected, too - it really isn't all about the kiddies.

Your view seems to be that my wife and I and our daughter do not constitute a real family, since we had to use a sperm donor to conceive. We don't deserve the protections that real families get, right? Because we can't have babies spontaneously, and the ability to make a family spontaneously is what qualifies families as real?

Well, you're entitled to your opinion, but your opinion is dumb.