About a 3.5
I read this in chunks, and it was very fascinating. Differences between genders in medicine should be a sort of 'well obviously' kind of thing but it seems that's not the case. Reading that there is more of a move to that is exciting, I just hope it continues in the future.
As far as how approachable this book and readable for a someone not in the scientific field I'd say it's fairly good. I know very little about medicine and bodies besides what I read in books and I was very rarely lost in this, if ever. It had a lot of very interesting facts and studies to look at, and taught me quite a bit. If it seems interesting I do think it's worth reading.