New Census study comparing gay and straight married couples:

Gay and straight married couples are demographically very similar in terms of likelihood to be raising children, age, income, race, whether they own or rent a home together, education levels, and employment. And both are unlike unmarried same-sex partners (and, I suspect, unmarried straight couples), who skew younger, more educated, more wealthy, are much less likely to be raising children, and are much less likely to have invested in a home together.

That's what the Census Bureau has concluded based on a sample of same-sex couples who live together and self-report as married, although the Census Bureau does not verify whether couples (gay or straight) are legally married.

Here's the Census Bureau chart, which you can enlarge by clicking on it:

If you can't see it well above, you can find it here.

There are many fascinating results here, only a couple of which I want to highlight now.

The data about child-raising is especially significant since one common argument in the SSM debate is that marriage is centrally about providing a stable environment for children. Straight married couples are somewhat more likely to be raising children (43%) than are lesbian married couples (38%) or gay-male married couples (32%). But the difference is not huge, and separates all three categories from unmarried couples, gay and straight, who are far more likely to be childless. And while lesbian married couples are more likely to be raising children, the difference between them and gay-male couples is not nearly as large as commonly thought.

Also, a higher proportion of gay male couples are married (or consider themselves married) than are lesbian couples (52% of gay male couples v. 42% of lesbian couples). Among other things, this means proportionately more lesbian than gay male couples are raising children outside of marriage (20% v. 8%).

The debate over gay marriage is moving from the abstract to the empirical. That's especially true as more states gain more experience with actual gay marriages. Unfortunately, the Census Bureau has resisted including gay married couples in the decennial census, arguing that DOMA forbids it. I'm not sure that's right, though of course the existence of DOMA didn't stop the Census Bureau from collecting this data. (UPDATE: The Wall Street Journal says the White House has now abandoned that interpretation of DOMA and is directing the Census Bureau to find ways to include same-sex married couples in the 2010 census.)

None of this demographic information proves that gay marriage "caused" anything in particular. Among other things, it seems likely that gay couples who fit a traditional profile (have children, own a home) are more likely to get married than those who don't. And of course it doesn't resolve the debate over whether states should permit gay couples to marry.

But it does fill in some important missing information about what gay families and gay marriages look like. And it turns out that, in some significant respects at least, they look a lot like traditional ones.

(HT: iMAPP)

UPDATE: Some caution about this Census data, here.

Some caution about Census data on same-sex couples:

Yesterday I posted some results from a new Census study comparing married same-sex couples and married opposite-sex couples, and comparing both to unmarried same-sex couples. The study concluded that in many significant ways — including likelihood to be raising children, income, home ownership, education, and race — gay and straight married couples were very similar, and unlike unmarried gay couples. The study also furnished evidence for some surprises, like the possibility that lesbian couples might be less likely to get married (or consider themselves married) than gay male couples.

But there's a potential problem in at least some of the Census numbers, which are inconsistent with some of the work done by demographers who have studied same-sex couples. Gary Gates, a noted demographer and researcher at UCLA (and a gay-marriage supporter), writes in an email to me:

One of the take-aways from the [Census] report is that married same-sex couples look quite a bit like their different-sex counterparts. That may very well be true, but one reason for the similarity is that it's quite possible that a very large portion of the married same-sex couples are, in fact, different-sex married couples who miscoded their sex. I've attached a paper (presented at the same session of the Population Association of America conference as the Census paper) that describes the difficulties in interpreting the married same-sex couple data.

From other work I've done, we know that married same-sex couples are 2-to-1 female and that women are more likely than men to be in a partnership. This isn't very consistent with the Census findings. Our analyses suggest that the sex miscoding problem among married different-sex couples creates more male same-sex couple miscodes than female. That could explain the Census findings.

There are several other findings that are not consistent with information we have about differences between cohabiting same-sex couples who are or are not in legally recognized relationships. For example, in a paper I published recently in Demography (with Christopher Carpenter), we show that those in registered domestic partnerships (in CA) ["RDPs"] have higher income and education levels and are more likely to be white than those who are not registered. These are the same patterns we see among heterosexual couples (comparing married v. unmarried) and contradict the Census findings. We also find no evidence of higher rates of child-rearing for those in RDPs in men and modest evidence of differences among women. Granted, RDP and marriage are not the same, but folks should be very cautious in interpreting the Census findings.

I think it's a very positive step that the Census released an analysis of the same-sex spouses. But it's just a first step. Much more work is needed to better understand who the married same-sex couples are and how many are miscodes.

If Gates is right about the coding problems, the miscoding would have skewed the results in favor of similarities since opposite-sex couples would have been included in the "same-sex" data. So gay and straight couples may be alike in many of the ways the Census Bureau suggested, but the new Census data do not necessarily support that hypothesis. A lot more work is needed, including more work based on the 2010 Census itself. In the meantime, modesty and caution about this new Census data are in order — more modesty and caution than I used yesterday.

UPDATE: For some interesting historical background on an especially noxious Census error, see here.