Andrew Sullivan spells
out why same-sex marriage is not a "slippery slope" to
polygamy:
I believe that someone's sexual orientation is a deeper issue than the number of people they want to express that orientation with. Polygamy is a choice, in other words; homosexuality isn't. The proof of this can be seen in the fact that straight people and gay people can equally choose polyandry or polygamy or polyamory, or whatever you want to call it. But no polygamist or heterosexual can choose to be gay. If you're not, you're not
The polygamy threat is increasingly being used as a cudgel
against gay marriage, and the premiere of HBO's "Big Love," about a
polygamous suburban household with "Desperate Housewives" kinds of
issues, may cause the rhetoric to get even hotter. I found the new
series well-produced and interesting, but (compared with some
hard-hitting documentaries I've seen) a sanitized view of what
polygamy is really about-which is typically not good for the wives
and children.