People misled by their own illusion

Blessed science has now revealed that eldest siblings are a little smarter than younger siblings, and that this condition is the result of family dynamics. Amid all the discussion of the NY Times article hyping the study, I haven't seen any mention of the part that jumpted out at me.

Moreover, researchers said yesterday that the results — being published today in separate papers in two journals, Science and Intelligence — would lead to more intensive study into the family dynamics behind such differences. Though the study was done in men, the scientists said the results would almost certainly apply to women as well.
...
Because sex has little effect on I.Q. scores, the results almost certainly apply to females as well, said Dr. Petter Kristensen, an epidemiologist at the University of Oslo and the lead author of the Science study.

So we've got a study which only looks at men and which unearths a result explained by family dynamics, and, we're told, the results will "almost certainly apply to women as well." This is just crazy talk. Even granting that 'sex has little effect on I.Q. scores' from some perspective or other, surely sex must be relevant insofar as I.Q. is impacted by family dynamics.