It is not complicated at all. Male people on hormones do not noticeably lose their strength, and certainly not their skeletal proportions and not really their density either.
https://onlinelibrary.wiley.com/doi/10.1111/joim.20039
First published: 27 November 2024
Results
Skeletal muscle size increased in TM (21% after 6 years) and decreased in TW (7% after 5 years). Muscle strength increased 18% after 6 years in TM (p = 0.003) but was statistically unchanged in TW.
And here is a paper regarding 'case by case' inclusion:
A GOOD DISCUSSION ON WHY CASE BY CASE DOES NOT WORK
"A unique pseudo-eligibility analysis of longitudinal laboratory performance data from a transgender female competitive cyclist"
https://www.degruyter.com/document/doi/10.1515/teb-2024-0026/html
Tommy R. Lundberg, Mary I. O’Connor , Christopher Kirk, Noel Pollock and Gregory A. Brown
Published 4 December 2024
Particularly good points:
"There are also concerns about whether the determining criteria for including a trans woman in female sports is a reduction in performance by a certain amount, or simply that the performance must be comparable to female athletes. This opens the possibility for sub elite or regional standard male athletes with no reduction in performance being eligible for higher standard female competitions."
ie. Suddenly a sub-elite athlete becomes an elite athlete
"The authors also appear to advocate for hormonal treatment as a means for some trans women to participate in female sport. This raises ethical concerns regarding the primacy of health and bodily autonomy."
ie. Health concerns due to hormone suppression
"Threshold criteria of how many variables an athlete is allowed to have an advantage in is not provided, leaving this to be an arbitrary decision on the part of the authors."
ie Arbitrary decisions because no published levels of advantage to compare against, and what is an acceptable reduction anyway because there will still be advantage.