@OldCrone
I think gender identity is a little more nuanced and complex than the single linear dimension of height which can be determined by a number alone!
A more detailed reply to this.
Suppose that there is some attribute of brains which is only ever found in female brains. By definition, this attribute, being exclusively female, will never be observed in male brains.
Now suppose that a man's brain is analysed, and he is found to have this attribute which it was thought was only ever present in women's brains. What this means is that the original assumption (that this attribute is exclusively found in female brains and never in male brains) was incorrect, and the attribute is actually found in both male and female brains, but is more commonly found in female brains. It doesn't mean that this man has a 'female' brain in his male body.
If there was a scietific test to determine whether a brain was male or female, it would actually prove that transgenderism doesn't exist in the sense of having a brain of the opposite sex to the body.
Well, as I've said before, I take no absolutist position on this - I don't believe in binary, distinct male and female brains.
But it is puzzling, isn't it? Why do these studies of trans people' brains tend to show structural and functional similarities to their preferred sex rather than their body sex? Why do you think this is happening?
The brain is so vastly complex that we really don't have a handle on this yet, and we may never do. But I don't think it's a simple question of one attribute.
If you were to say (and this would be an oversimplification, I am not laying claim to any figures) that there are 100,000 brain structures, and they all have different volumes or cortical thicknesses, and there are 100 billion neural networks, and they are all wired differently from person to person, and fire in different patterns, and then there are several different hormones as well, all being released in different quantities in different areas, from utero onwards (testosterone exposure in utero affects brain development) and affecting how well neurotransmitters or synapses work....
Well it's an extremely complicated picture, but it does not surprise me that certain combinations of all the above- certain volumes of cortices, certain models and firing patterns of neural networks, certain releases and activities of hormones, may be, overall and in general, more typical for female rather than male brains, and vice versa, and lead that individual through a matching, identification process with their apparently opposite gender. And there will be a lot in large, varied grey areas with mixed characteristics, and these people might identify as non-binary or be quite happy with being male or female as per their genitalia.
And even then, I'm not saying it's that straightforward, because I would think that in addition to what might simply be more typical for a male / female brain there is that element that leads them to determine it is important for them to claim that identity for themselves. So 2 individuals with the same sort of patterns of structure, activity, hormone presence that might lead an expert looking at their brains to to say 'yeah, I'm pretty confident that these 2 individuals are both male' and yet, when speaking to those 2 people one would identify as male, and 1 would identify as female. Now this might also be due to certain brain differences somehow connected with the importance of claiming identity- but not necessarily inherent to any female/male typical patterns. I'm not sure if that makes sense.
And of course there all the social influences at play as well, I certainly do not underestimate the impact of these, from countries which are more accepting of gender dysphoria but not of homosexuality, to dramatic changes in the number of 'female assigned at birth' young people who feel they are male.