This article is a good breakdown.
https://www.wcpo.com/transgender-mice-fact-check-trump-2025

The transgenic mice thing is for one of the several studies listed which I think we're justified in highlighting and poking fun of their lack of QA and reading comprehension in these releases since they're supposed to be representing the US and acting like drunken college students doing their homework the night before it's due.

The other studies are on the affects of HRT or "gender-affirming therapy" which is used by cis people all the time. Ever heard of a cis man going to get testosterone because he's concerned about his low T? That's gender affirming therapy. Most cis people don't realize how much "trans healthcare" affects them too. Some of this research is specifically on "cross sex" hormones and is probably more directly applicable to the trans community, but it also likely has broader implications on the science of hormones and side effects for everyone regardless of if they're cis or trans. This is one of several reasons why we say trans rights are human rights.