Despite title, this study did not investigate the question of sports advantage, at least not directly. It looked at physical fitness, concluding:
> While transgender women exhibited higher lean mass than cisgender women, their physical fitness was comparable. Current evidence is mostly low certainty and has heterogenous quality but does not support theories of inherent athletic advantages for transgender women over cisgender.
I don't find this study especially interesting or pertinent on the subject of sports advantage, as it only covers a small number of possible Whys, but doesn't touch Whats. It would be more useful for researchers to compare actual sports performance. For obvious reasons, these studies are probably not available for metaanalysis.
Yeah, it's just going to be pretty hard to really do any sort of good study here.
Like, for example, is the individual in question currently on HRT? When did they start HRT? What is their current testosterone levels? And when we dive into a specific sport, how do they actually perform?
The issue is that for any given sport there's like 1 or 2 transgender people participating in it.