Reference values are used as a diagnostic tool. In some cases, there are diferent references values for women and men. They are not based on hormonal profile, but on sex. In the case of FGR the formule used to calculate it is different for men and women.

Yes, the reference values are based on biological sex, because biological sex and hormone profile typically correlate strongly.

Taking exogenous hormones alter biochemical parameters of that individual, but that doens't mean you should evaluate them using the reference values of the opposite sex. This case show how that is a bad idea, actually.

Again., no, it actually doesn't. Because of course when the hormone profile returns to the one typical for the birth sex, you have to go by that.

About the employer example, a passing trans natal male could only be discriminated in the basis of a potential maternity if said male has made sure the employer doesn't know his actual sex.

Which actually a lot of transgender women do, since there is much less prejeduice against transgender people than against women (not saying there isn't prejeduice against women). In fact, "going stealth" (e.g. only intimate partners and medical caretakers being supposed to be in the know) is the goal for quite a lot of transgender people I know.

Also, if you think that thats how it works - what's keeping you (or other non-transgender women) from claiming to be a passing transgender woman at the next job interview? The employer isn't going to pull down your pants to check (at least I would hope so. If they do, it's most definetly not a place I would want to work at)

This doesn't justify the employer either way, but your example is about self-imposed oppression. Women can't opt out of ours like that.

Thing is, for transgender men it works the other way around - a passing transgender man (assuming stealth here) isn't going to be assumed to be able to become pregnant even if he can (because some who pass can, some who don't can't. Hormones are funny like that)

If you don't think so, just take a look at trans politics. Who is dominating the discourse? Trans natal males or trans natal females?

well, a significant reason behind this is that in the past there had been more transgender women than transgender men transitioning. Lately, this has been changing. Also, transgender men have been butting in on the discourse - remember this meme ?

Another reason is also, that the stereotypes against transgender people are quite different for both types, with transgender women being seen as dangerous predators and and transgender men as confused women. Which stereotype do you think is more likely to cause someone to become angry and outspoken against?

And finally, the opposite side also regulary forgets about transgender men entirely in the discourse. When people opposed to transgender people in the sex-seggregated spaces of their gender identity talk about that, they only ever think about it meaning that transgender woman would now be outside of the womens bathroom, they never think about it also meaning that transgender men would now be requierred to use the womens.

(reminds me of a case I once read. Essentially, a transgender men - who, based on what happend was clearly already passing- , living in a place where it was going by legal ID, was at a offical place to change his legal ID to male, had to use the restroom and - not wanting to break the law - went into the womens. Except someone was already there. Let's just say that "awkward" does not even begin to describe it)