I've decided to start posting some hints on Fashion Design. Some of these may be answers to basic questions or may let you know something you never considered!
The overlap of fabric under a button band is gender specific. Did you know that?
Men's clothing always overlaps so the the fabric lays Left-over-Right (if you're wearing the garment).
Jeans were originally made for men, so most women's jeans follow the rule for men's jeans. Some other types of pants, like corduroys, may follow either the jeans rule or the women's rule.