The U.S. Department of Housing and Urban Development (HUD) recently released the results of its study on housing discrimination against same-sex couples. The study used paired testing and found that overall, both gay and lesbian couples receive less favorable treatment than heterosexual couples in the online rental housing market.
The research was based on 6,833 e-mail correspondence tests conducted in 50 U.S. metropolitan markets from June through October 2011. For each test, researchers sent two e-mails inquiring about the availability of an advertised rental unit: one from a same-sex couple and the other from a heterosexual couple. Generally, the study found that same-sex couples received nearly 16% fewer responses to their inquiries than heterosexual couples. And unexpectedly, states with protections against housing discrimination on the basis of sexual orientation showed slightly more adverse treatment of same-sex couples than states without these protections.
This CNNMoney.com article has more information on the study.