Via Tyler Cowen, this is from the abstract of a recent paper that examines mortgage loans:
Interestingly, we also find that same-sex couples default significantly more (53.9%) than similar different-sex couples.
But that's not quite right. Here's what the paper itself says:
Male-male loan originations are associated with 2.053 percentage point higher delinquency rate relative to similar male-female applications. Given that the mean male-female delinquency rate is 3.81%, this result suggests that male-male applications are 53.9% more likely to be 90-day delinquent relative to similar male-female applications.... The coefficient for female-female is statistically significant at 1% level and is about a third of the male-male coefficient.
Lesbian couples are only about 0.78 percentage points more likely to default than straight couples. This difference manifests in loan rejection rates, which are considerably higher for gay men than for gay women (and both are higher than rejection rates for straight couples).
Why? The authors say only that "we are in the process of understanding
the mechanisms that drive these results." If the data were available (I suspect it's not) I'd be curious about the delinquency rate for married couples vs. partners. This is just a guess, but I imagine that married couples are less likely to default regardless of sexual orientation.¹
¹My reasoning is that partners can, if circumstances permit, just say fuck it, split up, and hand over the keys. Married couples have to get divorced, which makes their home part of a legal process.