DS goes to a mixed high school. They do a variety of clubs/groups throughout the year, and they've just advertised this one. The group that is coming in to give chats is from from a minority area of the city we live in and they help women who are treat like second class citizens because of their culture/race/religion. They may have been brought up to think this and the group helps explain that they're equal to men and don't need to put up with being treat otherwise.
With that in mind, they're allowing anyone in who identifies as a woman. Some of the young ladies who might want to go to this club are from cultures/religions that don't allow them to mix with anyone other than the same sex as them, and this may prevent them from joining the club and getting the knowledge they may need for a better empowered future for themselves.
I want to complain without coming across as a complete arse. I can't put across in words how this is doing the opposite of what they're trying to do by allowing gender in rather than sex.