TweetZedsDead, hi mate, I think most of the biggest guys are fairly masculine before they ever touch gear. This would often include a prominent jawline.
Personally I've never noticed gear effecting my jaw bones..... But Crankin'steiN makes a good point about gear use and the jaw muscles.
I'll post a case report in a minute that shows this. This juicer had huge jaw muscles on one side of his face, because he chewed lop-sided!