Weird Science Again
It turns out U.S. parents talk to their male infants about numbers way more than they do to their female infants. Lots more "see the five raisins" or "bring the two toys" when the little one is a boy.
Could this be what causes our adult daughters to do less well in math than our sons? See the article in Miller-McCune, a summary of research originally reported in Journal of Language and Social Psychology.