He's referring to a group that is selected based on their intelligence. In that case, it doesn't really matter what the distribution of the larger population is, because you're only talking about a group that is selected for their favorable attributes.
For someone to say that people who are already in a career, that is, already selected for their ability, are less suited because of their sex is kind of absurd.
No he is referring to the claims by the left who claim that there is little biological difference and mostly social constructional. Read the whole thing and the whole sentence.
For someone to say that people who are already in a career, that is, already selected for their ability, are less suited because of their sex is kind of absurd.