My friend, who is a study nurse, told me medical studies are often just done on men and then women are treated as small men when it comes to treatment later.
One of my female friends also wanted to earn money that way, and called them asking why. Their response was essentially that medical trials are very expensive, and men are a cheaper resource. I.e., women have ovaries and a set amount of eggs, and therefore would potentially be more adversely affected by complications from the experimental drugs, so the insurance was a lot more expensive.
But there is much historical baggage that are still hurting women today without most of them even noticing.
In fact, any study that arbitrarily excluded women without good reason would almost certainly be flagged by review boards before being allowed to proceed, and it would struggle to get accepted into journals.
Maybe this was true many decades ago, but it’s certainly not true in recent history.