>>681
You'll notice that Japanese copulae in general have no particular meaning. The most common copulae 「だ」 and its distal form 「です」 are linguistically thought of as predicating a sentence by connecting the subject with its predicate, though if you've spent anytime with Japanese you'll know that there is no difference in English meaning between 本社の部長はあほです、本社の文長はあほだ、or 本社の部長はあほである. Feminine copulae such as 「なの」 accomplish the same goal as 「です」 or 「だ」 but are primarily used by females or indicate female speech.
I can't say whether its "normal" for males to use 「なの」 but I seldom hear it. More likely, its the auxiliaries 「なのだ」 or 「なのです」, which are used across gender.