What you said about a friend of yours or a relative mentioning it says everything. First off, if they had gender reassignment, they wouldn't need to mention it for you to know.
You don't know what I think.
You must explain to me what the Pantomime Horse has to do with gender-reassignment. As best as I know a pantomime horse is a stage costume that requires two actors to operate it and who could be any gender or combination thereof since the audience can't see them. Are you talking about the UK Glam Rock band Suede from the 80's? Glam rock was and is known for androgyny.
You so often Think you know what others Think as you post about it.
Friend or Relative I'd tell them to Stop being so Fucking stupid & or go seek psychiatric help
As their brain isn't working correctly.
And then likely I'd tell them to Fuck off
The Pantomime horse is a fake horse Pretending to be a real horse
Just like the Men pretending to be women & women pretending to be men.
Neither they or you can change Biological sex- you & them can play pretend
As much as you like just don't expect others to play pretend with you.
Go on now tell me that Biological sex can be changed........... Along with chromosomes..........
And Bone structure............