Last week, my sister and her 25-year-old son were visiting. The son has been 'identifying' as a woman for about 6 years now, and I've always made it clear that while I have no problem with him, but that I won't be referring to him as female; he's been understanding, and never has a problem with me using his real name, etc. - he's always been incredibly sweet and polite, and we've always got along in the past. Anyway, when they were over last week the news was on the radio about the gender recognition act, and he and his mum started talking about how awful it was, to which I confess I rolled my eyes a little. After they had been talking for about five minutes, I couldn't really contain myself, and added - quite reasonably - that the policy was just to keep creepy men out of women's spaces. Sister went quiet, and after a bit of a back and forth with nephew, he asked "Well I would use the women's loos, does that make me a creepy man?". By this point I was seeing red a little and simply replied "If the shoe fits". Only contact I have had since then is my sister asking me to apologise - I've said I'm perfectly happy to apologise for how it came out, and that I know he isn't a pervert, but that I won't back down on the fact that he shouldn't be in women's spaces. AIBU, or should I stand my ground?