The gender issue is an interesting point. There's a well-known saying in dog-breeders' circles: "They don't call 'em *****es for nothin'". They tend to hold onto females as breeders, and males as companions. Generally (stressing "generally"), males tend to bond more with their handlers, be more aggresive, more affectionate, more responsive, and more interested in attention. All of these things tend to make them easier to train. Females are generally more laid back and less demanding of your attention. If you need clarification on this point, just talk to a couple of breeders -- they're usually eager to discuss experiences with their pups.

Ron
http://germanstar.net