Of course, the guitar body, particularly when related to the bodies of cellos and other stringed instruments, would often be seen as a female form, with a slim waist and large hips. Anyone who has seen that classic portrait of the nude woman from behind, sitting down with the two f-holes painted on her back will know what I mean. But yes, the guitar neck is often used as a phallic symbol - particularly among 80s rock/shred etc -, this could have something to do with guys feelings of inadequacy? Maybe it's just that guys find it too hard to keep their hands out of their pants for a whole set...
As for that comment about women not pl;aying acoustic guitar because of their breats, do you actually know any women? Have you actually seen a woman hold a guitar? If you had, you might realise that it's not really problem, breasts are not like annoying air balloons that hinder movement, are you going to suggest that they can't play sport either?