> A rudimentary exam could do it.
But what does this exam actually entail? I am looking for an actual specific class of test or set of tests.
> Entirely wrong.
Please elaborate. What mechanism drives those characteristics if not hormones?
> These aberrations exist but are incredibly uncommon. I think I'd read of a single woman thus far with XY chromosomes.
A woman having a 46,XY karyotype has odds of about 1 in 100000 which would put the likely number of women with a 46,XY karyotype at almost 40k people across the globe. It's undoubtedly rare but that is still a lot of people. While these women have lower hormone levels without treatment, they have otherwise completely healthy female bodies which results in most women never identifying that they have the condition in the first place. Unless a genetic test is performed, it just appears as if these women have hypogonadism which can occur for any number of other reasons.
The opposite (a man with a 46,XX karyotype) is even more common with about 1 in 20000 odds which sits the population at close to 200k people. But once again, because it results in relatively little to no health issues or abnormalities beyond low hormone levels and infertility (hypogonadism), it is often either left untreated or is treated without identifying the cause.
Similarly, a male with a 47,XXY karyotype has a very similar if not almost identical experience as a 46,XX male. With odds of 1-2 in 1000, that's 4 to 8 million people who don't fit that standard sex definition.
> What do you think is driving the need for constant hormone replacement?
Remember this is talking about an individual without their sex organs. If they are removed or are non-functional, the individual almost always needs hormone replacement because without those organs to produce sex-related hormones (which effectively serve as the control switch/regulatory system), significant chunks of the endocrine system stop regulating themselves properly and the individual ends up with hormone imbalances.
In the case of SRS, the hormone producing sex organs (either testes or ovaries) as well as anything else that isn't needed any more are removed and the remaining organs are reshaped to match the form of their counterpart for the other sex. At that point all sex-hormone production is artificial/manual just as it would be for an individual of that sex who had those organs removed due to health issues (or that have those organs non-functional).
---
Trust me I've looked for any medical or biological evidence that human sex characteristics excluding the primary reproductive organs (testes, prostate, penis, ovaries, fallopian tubes, vagina) are driven by anything other than hormones. I can't find any evidence to support that fact. The prevailing opinion of the medical community seems to support the fact that sex is driven by hormones and organ presence rather than any other mechanism. If you can find a medical source that supports otherwise I would love to read it and this is a serious request because if by chance I'm wrong there's no benefit in me staying that way.