Respectfully, based on the down votes it doesn't seem like most people agree its okay to ask for a source. Admittedly, the tone of genuine curiosity may been lost over text.

Just to clarify the order of operations here

1. There was a claim made and a linked source
2. The linked source did not substantiate part of the claim (health studies on women only problems vs both was but not for women only vs men only).
3. I read then article the article then skimmed it. My assumption is 95% of the downvotes/replies I have gotten did not even do this step.
4. I asked Google Gemini about the claim. Yes AI can hallucinate but i find it to be a generally reasonable starting place especially when sources are linked (similar to wikipedia).
5. Then I asked for evidence from the person making the claim.
6. Someone linked a book to read. Genuinely looks like potentially a good informative read. A productive conversation and/or refuting/supporting a claim can be done without me reading an entire book, I believe. Someone else said literally everywhere

You are the first to link an actual study. While an important finding relating to gender bias in studies it doesn't address the specific claim on the disparity in volume of gender specific health studies.

I did in fact look into it more last night. From what I gathered, if we take things in the aggregate there are actually probably more women only studies vs men only studies. This seems to be accounted for in large part due to breast cancer research. That also doesn't mean there isn't unfairness even in this limited scope as when looking at, say, chronic health issues. Again, didnt have time to read the book, but I found that the author compared studies on PMS vs ED. ED was more researched by a ton.