No no, my mistake, I wasn't just including practicing physicians when I said doctors. Sorry about that.
My point is that there is no room for opinion if you include hard evidence involving genetic markers. Also, there should be no room for opinions if we have the ability to use such things to define it. I'm not saying we have regular doctors (with opinions of their own) show up at congress to tell them what to do, I'm saying we get the necessary peer-reviewed research into what range or spectrum exists, then make informed decisions thereof, which would be enacted by the medical community under guidelines put forth according to the aforementioned research.
No offense taken; I tend to overreact to this sort of thing, being both a PhD who has to work with a lot of MDs and interested in GSRM medical issues on a more personal level. Trying to bring the scientific/medical consensus on these issues into the law is a laudable goal, but I still just don't think we're ready scientifically to present as concrete a case as we want legislatively.
I mean, say you bring in the experts and the first question some Senator asks is, quite reasonably, "are there two sexes?" The most honest answer is probably "in a statistical sense, mostly yes, but to get there you have to include enough different anatomies and physiologies under the two umbrellas that they aren't really informative anymore, so not really in any actionable way."
Okay, perfectly reasonable question two: "How many sexes are there?" Here's where the shrugging starts. It depends how you define sexes; if you go purely reproductively, you can start implying that lesbians aren't women because they're behaviorally reproductively isolated from men (leaving aside trans women purely arguendo), or men who have gotten vasectomized aren't men anymore, and so forth. Anatomically, physiologically, and (epi)genetically there are too many exceptions to count and no clear way to tell which are actually maladaptive in and of themselves.
At the end of the day, the truest and most confusing thing we can say is that life is a hugely successful way of capitalizing on stochasticity on scales from the molecular to the planetary, and as a very successful species we have robust and adaptable ways of dealing with whatever our sex chromosomes throw at us so there's not a clear basis for calling one outcome a disorder and another a different sex, and even at our most viscerally biological our reproductive fitness as haplotypes doesn't necessarily correlate with the number of children to whom we personally pass them on so even that doesn't work as a guide. None of this is to say that there aren't, in fact, actual mental disorders regarding sex and gender, of course.
I'm just saying that if you want indisputable science on which to build a law that provides everyone with what they need by category, we don't know how to draw all those categories yet.