I always find the prison threads interesting. A lot of trans* people who would be incensed if their gender identities were not recognized and who recognize that the trope about men in women's facilities in the rest of the world is absurd, suddenly start insisting on special tests for prisoners and getting very concerned about men claiming to identify as women so that the men can go into women's facilities. It's the one time when i have seen large numbers of trans* people start to agree with a group like the Family Research Council on both the position (trans* people should be housed based on genitals) and the reasons (men will pretend so they can get transferred to womens prisons). But is there any evidence of that? I'm not aware of any.
Historically, prisons have general housed trans* people based on anatomy. That means men in women's prisons if they are FtM and women in men's prisons if they are MtF. The main problem with this has been assault, especially sexual assault. In the US, we have made a legal and policy judgment that says people in prisons should not be raped. It still happens sometimes. And it was happening to trans* prisoners a lot more than other prisoners, sometimes with participation by prison guards. This still happens in many prisons.
This placed prison administrators in a quandary. They couldn't allow prisoners to be raped. They started (and still continue) losing lawsuits alleging that the prison staff did not keep the trans* prisoner safe. So they couldn't house them based on genitals alone. And of course they couldn't respect a trans* person's gender identity because (they believed) anyone with boy parts is male and should be called he and anyone with girl parts is female and should be called she, no matter how they might identify. So some prisons began automatically housing trans* prisoners in "administrative segregation" a/k/a solitary confinement, either on arrival or after the trans* prisoner is assaulted.
But solitary confinement poses other problems. It involves isolation inside of a cell for 23 hours a day without other contact from people. This creates health problems--especially mental health issues. And it also isolates the trans* person from access to programs available for other prisoners. For example, educational programs are often available to help prisoners obtain credentials like a GED so that the prisoner may be more likely to have options on the outside world beyond committing crimes. It usually is used for short periods of time as a punishment for the worst behaved inmates. But for transgender people, it is used for long periods of time, including entire sentences. Synthia Blast, for example, has been held in solitary for more than a decade now. So what we have now is transgender people being punished much more harshly than cisgender people solely because of their gender identity. That practice is increasingly being challenged as well on Eighth amendment grounds, among others.
Now we see two other trends emerging, partly due to standards promulgated by the Department of Justice pursuant the the Prison Rape Elimination Act. Some prisons are, for the first time, housing trans* prisoners according to their gender identities. The Harris County jail in Houston, Texas, is among the higher profile detention centers trying this. They began about a year ago and so far there have been no problems that I know of. More specifically, there have been no reports of men claiming to be transgender so they can get into the women's facility.
Another approach being tried is the creation of "trans* only" detention facilities. Rikers Island prison in New York is a high profile example of this approach. Their facility began operation last month, so it's too soon to say much about how it is working. I'm trying to provide factual history here, so I will refrain from stating an opinion on it.
But one thing that shows itself to be true over and over and over again in every setting is that there are far fewer problems when one respects trans* people's gender identities. It works better in locker rooms, bathrooms, and other places. And prisons seem to be no exception. Time will tell if I'm right about that . . . but evidence so far seems to suggest the correctness of that view.
If there were evidence of a problem with men claiming to identify as women, or vice versa, just to get into the opposite sex facilities, then I'd agree it was a concern. But I've seen no evidence of that being an issue. When I advise policy makers, I prefer to advise them based on things that are actually happening. When they raise hypothetical situations that just aren't happening, I advise them to focus on real problems instead of issues that don't exist. And it's the same thing here unless someone knows of a rash of this happening that I have somehow missed.