Lovely. Two women marry in Massachusetts, and have a baby via some artificial means. After three years, one woman moves to Utah and takes the child along. She now is a citizen of the State of Utah.
What recourse does the other woman have?
That's an interesting one. Here's one for you too.
A 17-year-old boy and his 16-year-old girlfriend get married in Mississippi. They didn't need parental consent because the law of the state allows them to marry at that age anyway. Now let's say they happen to have a kid, and the wife decides to hightail it with the kid over to her relatives in Texas, where state law dictates that marriage licenses can only be granted to over-18-year-olds, unless parental consent was given.
What recourse does her husband have?
You see, the situation you describe is not an example of something that will begin to happen if gay marriage is permitted, because this kind of legal wrangling is already taking place.