If we're considering testosterone to be a PED, perhaps we should ban everyone from sports...
On a more serious note: why not advocate for putting people into "testosterone-level groups", similar to how boxing, etc, do it with weight classes? Rather than just excluding trans women from competing.
I also feel I have to ask: how do you feel about your niece losing in competitions to cis women who have biological advantages, such as higher (natural) testosterone levels, longer limbs, bigger hands, smaller busts, etc?