Polygamy. Now it had to happen eventually. Here is an article about the recent suits being tried to justify polygamy as legal according to the Lawrence v. Texas ruling by the Supreme court. The polygamists seem to have some good arguments here, whereas before Lawrence they were stuck one shut. Justifying a polygamous marriage may not be the same thing as what was decided in Lawrence, because it just said that whatever adults do sexually in the privacy of their own home cannot be infringed upon. The pro-polygamy lawyers argue that since it is part of some religions (Mormons, et al) to discriminate would be an infringement on their 1st amendment rights regarding free practice of religion.
Of course the government doesn't have to recognize any marriage past the first one. Anyway, read the article. We all knew that once Lawrence came down that polygamists would be next.