I'd also like to know if the results would be the same if they controlled for income levels, or for self-confidence levels, etc. It does seem rather suspicious.

(I'd buy that there's a difference - because (some?) women have it hammered into them that they need a Reliable Man, that (if interested in reproduction) they have to think of their future children, etc. etc. etc. But it's not any ~inherent biological instinct~, it's social programming.)