mysteries of the universe number 42

What exactly is it that makes guys who play the guitar so attractive to women?  Why don't we see piano players or saxophonists or trumpeters basking in the same sort of female adoration?

Seriously, there must have been at least 12 girls crammed into one of my floormates' rooms last night as three guys gave an impromtu concert.  Granted, they were actually pretty good, although they'd sound better if they didn't sing along.   None of them seem particularly good-looking nor have sparkling personalities, or at least not to me.  Then again, one of the guitar players was that weird dude who's always walking around without his shirt on...