Much of the dreg published back then by Bailey, Blanchard, Raymond and others has long since been discredited by the scientific community and before you say anything: no, not because of ‘wokeism gone mad’.
One pillar of their research back then (and in part - to this day) was insisting trans women are men who suffer from a condition called autogynephilia (a fetish for seeing oneself as an attractive woman - the theory Dreger is referring to). And yes, a considerable amount of trans women met the standards he set for this condition. But it turns out, the percentage is even higher among cis (non-trans) women. 93% of them qualify. I guess the remaining 7% are the real women.
https://pubmed.ncbi.nlm.nih.gov/19591032/
If you are sincerely interested I recommend reading the works of Julia Serano. This piece about the book you mentioned is a great place to start: http://juliaserano.blogspot.com/2015/04/alice-dreger-and-mak... If you’re just looking for ammunition to throw at trans people because you don’t like them existing, as very much seems to be the case with Alice Dreger, I can only hope you’ll find a more meaningful and positive way to spend your time.
https://link.springer.com/article/10.1007/s10508-022-02359-8
(Bailey's also an associate of Steve Sailer, which is reason enough to doubt his honesty)