The opposite claim - that men and women are equal has the same problem. As far as I can tell we don't know how men and women are different other than a few physical factors related to breeding or hormones. Worse it is a controversial subject that you probably shouldn't study because when your results are other than what someone wants to believe true they will make your life difficult. Either you find a difference or you don't - either way you confirm the bias of one group and contradict the bias of the other.
I think there are real differences, other than the two I mentioned, but there is probably a lot of overlaps where you can find plenty of exceptions.
I think there are real differences, other than the two I mentioned, but there is probably a lot of overlaps where you can find plenty of exceptions.