Mostly the arguments for gender segregation in housing have to do with sex. If men and women are living together, they have to be having sex. The same is never assumed for same-sex roommates, but that does not mean the same is not true. Many gay men feel more comfortable rooming with women while genderqueer individuals tend to have a hard time finding a place within a forced housing situation. When gender non-conforming people are placed into rooms based on their sex at birth, it can cause difficulties when expectations are different than what is actually encountered. If a woman is expecting to room with another woman and finds she is rooming with a transman, it can make for an uncomfortable situation.
Some of these housing situations can sometime be dangerous, and the more people who know the need for gender-neutral housing options, the better. The NSGC is working to gain support for these options throughout the country. On their website (www.genderblind.org), they suggest ways to start a movement on your campus, so go online and check it out.