Now I know this is a generalisation so let's not get distracted by a nitpicky analysis of that aspect but I bet I (or anyone) could go into any house and tell the gender of the occupants (female, male or mixed) just by the contents of their bookcase.
In our house the only overlaps of books were freakonomics, an atlas, a dictionary and to kill a mockingbird.
DP has lots of military books and crime and horror fiction. I have reems of feminist titles. I would imagine that alot of couples' collections are not as polarised as ours but there definately is a gender split isn't there?
I've heard that whilst women are happy to read book by male authors men are less willing to read female authors. Is there an unknowing sexism in this?