Despite falling under the LGBT heading myself, I don't have any special insight here either, but as far as I can tell it's really just a signaling behavior. We

Despite falling under the LGBT heading myself, I don't have any special insight here either, but as far as I can tell it's really just a signaling behavior. We've been conditioned to see pink -> feminine, blue -> masculine, and I believe that translates beyond just the pastels we're used to seeing small children in. When I think about a real "man's man", one of the first things to come to mind is a guy in blue jeans -- I can't help but think that that's related. Again, unscientific, but it makes a good bit of sense I believe.