This kind of thing is the inevitable progression of trans ideology, and we're also seeing it with the trans-age, trans-disabled etc stories coming out more and more.
If you can insist that you are something that you're not (i.e. the opposite sex) and other people can be forced to agree that you are and treat you as if you are, and you can demand "medical treatment" to make you more like that thing, then we're already in a ridiculous, nonsensical situation. It then makes no sense for it to only apply to sex - certain types of people, whether gullible, predatory, narcissistic, misinformed, profit-seeking or whatever - will then seek to apply the same logic to everything else, and that's what's happening.
Ultimately we have physical bodies and physical realities and in most cases, trying to change them to be what we would like to be has drawbacks and tends not to work very well, or at all. Likewise not changing anything but passing laws that other people have to agree that you are something you're not, is going to be problematic in numerous ways. Lots of people have been conned or shamed into thinking it's somehow magically true for sex/"gender", but the more it spreads, the more obviously it's nonsense.