Same-Sex Y2K?

After reading an article in the SF Chronicle about benefits issues for newly wed same sex couples, it occurs to me that there may be some very interesting tech issues coming up. I'm very happy to live in San Francisco which has been ground zero for the same-sex marriage fight. I'm looking forward to equality for all, but I wonder what kinds of hidden problems will come up when same-sex marriages become legal? Much like the work that had to be done before the year 2000, I suspect there are a lot of hidden assumptions in many databases around the world. How many systems out there have some "sanity" check to see that spouses are of opposite sexes? I doubt this will be anywhere near as big of a problem as Y2K, but I bet there will be some surprises.