i'm pretty sure it doesn't matter if you pitch your voice down in audacity, since UTAU is going to repitch your samples in the program anyway. since every UTAU has a range that it sounds good in, by pitching down the samples, you're not extending the range, you're just using a lower note in the range.
something you might try, though, is mimicking that sonic the hedgehog voice. not accurately-- think Arin Hanson's impression. you add a little bit of intensity and growl to the recording and you might just end up with a "teen" voice.
still, whatever range you work with them in, whatever flags you use, will go a long way toward making them sound male or female.
(but psst! a secret! if you're willing to spend a little time on your voice,)
practicing good singing technique and doing scales will help you stretch your voice. pitches normally out of your reach will be readily accessible if you sing from your diaphragm, seek to hit the spots with the best resonance, and make sure to use good vowels. and don't forget to open that mouth! your mouth is your megaphone! if you can drop the bottom of your pitch by, heck, even an octave, depending on where you start out, you'll want to rise up a few notes into a comfortable pitch and record there.
this sort of vocal stretching takes months, though, and you're going to have most effective success under the instruction of a vocal coach/singing instructor.
if you're looking for a quick fix, however,
http://www.artofmanliness.com/2011/11/13/masculine-voice/
https://answers.yahoo.com/question/index?qid=20081212164701AAtN1WA
further, the "do a yawn" trick isn't so much for recording, as it is for getting your vocal cords in a position to record a more relaxed, lower voice.
my posts are so disjointed =__=