As scary as this can sound, I think you have to look at this from a 'majority rule' standpoint.
Women probably make up ~40% of amateur athletes. Probably a little less but not too much since most schools have men's and women's teams in most sports. I'm docking 10% because there isn't a women's equivalent to football, which has a lot of players on a team.
Now, trans athletes are - what - 0.1%?
We cannot risk damaging women's sports for a very small minority, when there is evidence that allowing them in women's sports will damage the sport.
I don't want to make trans athletes into outcasts of society (IMO many of them, especially at the HS and lower levels, are more victim than perpetrator) but we need a different solution.
This is not to say that the trans athletes would automatically win. In Powerlifting (where USA Powerlifting has royally pissed me off with this) there is a girl in Seneca (Clemson Student) who will probably still kick their ass. Of course she can probably out bench press and squat 95% of this board as well.....
And no, she does not look like a Russian Beef Herder.