Having on one side the top 1,000,000 male surgeons and on the other side the top 100,000 female surgeons makes a difference, which is really hard to measure. Of course both are not the top surgeons, but it is just harder to find more of a kind. Imagine looking for 100,000,000 male surgeons, which is probably impossible given the education demographic in the US.
10x difference isn’t a problem. You have to look at ratios.
Having on one side the top 1,000,000 male surgeons and on the other side the top 100,000 female surgeons makes a difference, which is really hard to measure. Of course both are not the top surgeons, but it is just harder to find more of a kind. Imagine looking for 100,000,000 male surgeons, which is probably impossible given the education demographic in the US.