Well, I think there is a correlation, in that more of us have a certain digit ratio than cis people. But it isn't all of us, so it really does not actually matter and def is not 100% proof of anything. PS I could be wrong, I haven't read about it in a while.
The brain thing, I do believe that is more conclusive, in that results have been reproducible. I also think I heard they have been able to study something brain-wise on living people, but again idk for sure. Just something I skimmed a while back or something.
I am less interested in these things than I used to be, otherwise I would be less unsure of everything

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