Is it not correct that limits of testosterone for TW are 2-3 times that of women? If a woman had the same blood levels they'd be banned for dopping? Lowering the testosterone any further for TW to that of women would be very dangerous physiologically?
At least a factor of 2 over normal female range.
If a woman had the same blood levels, it would pretty much be evidence of doping, but if somehow she had those levels and was healthy (not really possible), then she wouldn't be banned. There's no limit for females. (There is for athletes with XY DSDs like Semenya, who are effectively male).
Not sure about the lowering further part. 10 nmol/l (the limit) is at the bottom end of normal male ranges, so I guess, yes, lowering below that would be more unsafe. But a male would end up lower if they'd had surgery. I don't know why the limit was set so high.