Women's Oasis or Transphobic Spaces?

I really, really, really, really like this post by PG on women-born-women spaces and how they discriminate against Male-to-Female transsexuals. I've talked about exclusivist spaces before (in blogging, actually), and I've also discussed the plight of internal minorities, that is, people who are a marginalized minority within yet another marginalized minority group (e.g., transgendered women, Black conservatives, lesbian Jews). There are extraordinarily thorny questions involved in how the super-minority group (in PG's post, women) treat the sub-minority group (transsexuals). PG's treatment of those issues, and her reminder that internal suppression of sub-minority groups hurts both the movement as a whole as well as coalition-building with outsiders, is very well argued and essential reading.