Is It Better To Have One Male Dog And One Female?

There are some factors there. Some breeds/dogs it is not recommended to have same sex at all, ever. Some breeds/dog's it's not a good idea to try and bring in another dog at all after a certain point. If your dog is dog aggressive or similar temperament you have a better chance bringing home a puppy of the opposite sex. If none of the above it doesn't really matter. So the details of the situation (breed,age,sex, history, family details ect.) would be needed to give a more accurate answer to each specific circumstance. There is almost always an adjustment period though even if they will end up being fine of usually about 2 to 4 weeks where they figure out pack placement or an older dog teaches a puppy their rules and things like that. And of course spaying and neutering is best for health and behavior and also helps cut back on aggression.

To Bgirl525:
You obviously don't have any "real" experience with dogs.  Here you are referring to the Doberman Pincher.  These dogs are known to be hyperactive and have puppy-like traits that remain, in this breed,  for a good long time.  The Doberman takes patience and constant teaching.  In most cases you will find that males sometimes become more territorial and much more vocal (barking/growling) than females.  However, where protection and problem solving are concerned...sometimes the females have the upper-hand.  After all, it is the female that has the puppies; you will find mother-like instincts are quite present there.

Basically, gammon is cured, gammon ain't.