The general is evident: trans women are women, and thus belong at womens' colleges. The specifics and nitty-gritty are what make this issue an incredibly frought one. Let me bring up a few of the issues I've heard in various spaces and try to address them. I'll try to present a nuanced view for a nuanced problem.
A first issue that strikes me is Bryn Mawr's placement in wider environmental circles, not just the protective Bryn Mawr Bubble that has been such a wonderful safe space for us. The world, sadly, is nowhere near as accepting of trans people as the Bryn Mawr community, and even we have had serious issues, on not just the trans front, but also race, class, and disability, to mention a few. (Look at the recent issue with the students with the Confederate Flag) As much as it is painful, wide publication of our status of having accepted and continuing to accept members of the trans and genderqueer communities under the umbrella of the women's college might be turned against us by the wider press. The media has a huge trend towards sensationalizing and distorting even the simplest of issues, and thus such a complicated issue as that of the admission of trans women and other non-cisgender people is highly likely to be distorted in a way that would be damaging to the mission of Bryn Mawr. Mills College was incredibly comprehensive in the way they made their decision--they have a ~40 page report detailing their research that supports their admission policy. We do not have any such research going on at the moment that I know of. We also thus have to ask ourselves what the impact of such negative publicity would be on our mission, and we might not well be able to handle the repercussions. Mount Holyoke has gone out on a limb, and is going to end up being the test case for many institutions.
A second issue that strikes me is that we are unlikely to have good support systems in place for trans women, at least in any greater volume than they likely have already been here. We already have incredible issues handling race and disability, and gender issues with the trans men and genderqueer students who are here. We need to be incredibly careful in our handling of this issue to not out any trans women who do not want to be out. Though Admissions has told us that we have indeed admitted trans women in the past, no alumnae or even possible current students are coming forward to speak to this issue. This isn't that surprising, though--trans women have one of the highest murder rates of any marginalized group, and run more risks than many. I would love to hear more from the trans men who are already here about why they wanted to come here, and how their gender has affected their experience here. I don’t have enough information to form an informed opinion.
Bryn Mawr needs to spend a little more time researching the issues at hand before putting out a comprehensive statement on our admissions policy, and putting in place measures to handle a new group that can need incredible confidentiality. Depending on how we define it, it could indeed mean a change in mission. In the meantime, we do need to make clear that trans women are welcome here, but very carefully, and in trans-friendly spaces. We need to be very careful about how we do it, so we don't risk outing the trans women who have already been here, or who might already be here, or who are being admitted. We also need to keep in mind how publicising this might affect the groups of women here already, or groups that we have traditionally attracted in the admissions process, and how negative publicity might affect them. Additionally, we need to figure out how to handle education who might not have been exposed to trans issues before attending here, which is likely to be the majority.