Banning all transgender atheletes due to one or two high performers does a dis-service to all transgendered atheletes though.
It's not all female atheletes who are being disadvantaged, but it WOULD be all transgender atheletes disadvantaged.
I have no problem with transgender atheletes as long as the competition guidelines are clear, obtainable, and the students stay within the guidelines.
If it becomes an issue where all transgender students are repeatedly setting records and such, making it impossible for non-transgendered kids to compete? Then you change the competitive guidelines, you don't ban an entire class of kids from competing.
For example:
Must be on puberty blockers for x months or years.
Must be on proper hormones for x months or years.
Heck, they might even require re-assignment surgery.
The problem with guidelines like this, is the people opposed to trans atheletes are ALSO opposed to puberty blockers, hormone therapy, and re-assignment surgery.