Dr Fond of Beetles useful Twitter thread that discusses CAIS (Complete Androgen Insensitivity Syndrome) which goes beyond discussions of testosterone advantage.
What if we could identify a group of people who had no T? Not female typical T, not lowered to below typical female levels, but no T at all. We’d predict, if T is the only factor that confers sporting advantage, such people would be pretty damn poor at running. 6/
This group of people exists. XY genetic males with Complete Androgen Insensitivity Syndrome (CAIS) can produce T, but use not a single molecule of it. They are functionally T-zero. 7/
...
The IOC logic (and that of invested parties) tells us that CAIS females are going to be the least competitive of all females. After all, non-CAIS females have at least some T that they can put to use. 9/
The frequency of CAIS in the general population is 1 in 20,000. The frequency of CAIS in female athlete cohorts is 1 in 420. CAIS is nearly 50 times more prevalent in female athletes than in female couch potatoes. This is a massive overrepresentation. 10/
CAIS females succeed as athletes way more often than non-CAIS females. How puzzling that the only thing the IOC asserts confers sporting advantage is functionally absent in these females with clear sporting advantage. 11/
Whatever underpins CAIS female sporting advantage, it is independent of functional T. Thus, the IOC position that T is the only factor influencing sporting advantage - and - the only action a male must take to “fairly” compete against females is to reduce T, is untenable. End/
threadreaderapp.com/thread/1070097483408248835.html
or the following original if you prefer to see comments and discussion:
twitter.com/FondOfBeetles/status/1070097483408248835