Plenty of females have male muscle mass due to high sensitivity to androgens or/and
producing more androgens than average. That's in the genes, but not in the sex genes.
After awhile, the male muscle mass goes away and your left with not more muscles
than your average world class female athlete, which in no way ressembles
a normal woman by her muscle mass. There is a class of events where
a TS would have a huge advantage, this is the possible exception
to allowing participation. I'll talk about it more later in this response.
The most funny thing of all is a woman with AIS (male DNA with a complete female phenotype)
which gains nothing from being "a man", since her body doesn't react at all to androgens, yet
should she be banned?
The sport where there is a the biggest difference between male and female performance
is ironically, the sport I used to compete in. High Jumping. This is a sport where a male athlete
with local college level performance could transition and if kept in shape easily become a
top world athlete. My personnal record is higher than the female world record right now, and I've jumped on 30 occasion higher than that record. I could qualify for the female high jump olympics in Canada, jumping on one leg with no run-up, that's how ridiculously different the male and female records are.
The main difference between male and female athletes is not muscle size but muscle fibre.
That' means the real issue would be in power sports (100-200 meters, long jump, high jump,
weight lifting). In fact, field events and short track events are power sports. That's why
there has been so much steroid problems on the track. The energy is expended in
a very short period of time, high jump needs the most power and short twitch fibers.
Most olympic sports are not power sports but endurance/resistance and technical sports.
In those sports, after a few years, there is no marked advantage for a TS woman.
Michelle Dumaresq didn't even qualify for the olympics, she's not even on our national team,
let alone winning an event at the olympics.