In 2012 or so I partook in a course of self-defense for women. Everyone involved was female and it created that special safe, open atmosphere that you only have when only women are in the room. Several women opened up about their past experiences with sexual assault, including one teenager who tearfully told us about her cousin raping her when she was 14.
Years later in 2018 I decided to take another such course to refresh my knowledge. On the first day of the course I discovered that there was a trans-identified male among the participants. I had never before been confronted with any trans people or topics so I went along with it despite my immediate discomfort. It was a large rather bulky man in his 40s who wore strong makeup, a skirt and high heels - the only person who had not dressed appropriately for a day full of physical exercises.
I later privately asked the course leader to not pair me up with him in anything and she agreed though she was clearly taken aback by me asking. Over the 3 days of the course, the atmosphere was tense and uncomfortable, and none of the women talked about their private experiences or really talked much at all. When the course leader was talking about statistics of male violence and such, this man made a sad face & kept nodding along as if he had any idea about it all. He was also the only one apparently unaware of the tense atmosphere his presence created as he kept laughing and trying to start conversations with the women.
Overally there was a clear difference in atmosphere and comfort between the two courses I had experienced. While there was no explicit mention of the course being for 'cis' women only, it was clearly advertised as being for women, and any trans-identified male with common sense or respect for women would surely understand that this means they should not be present in such a female space.