Don't be silly, girls aren't asexual--they just haven't met the right man yet! And in this case the right man was obviously the creepy grandpa, the sex symbol of incestuous relations as proven by all the fantasies about him, except that he wasn't creepy and the incest totally didn't happen because incest is just as much a myth as asexuality.

...Yeah, that makes sense. It hurt my brain to type.