Overview: In some ways, choosing between male and female dogs is a matter of personal preference. However, there are some differences. It is important to evaluate these characteristics and determine which sex would fit in best with your home situation when you choose a puppy. Many people have strong ideas about whether a male or female German Shepherd is better. These ideas are usually wrong, but a few differences do exist.
There is no ‘hard’ data that supports one gender over the other with respect to intelligence and trainability.
Males: The males are typically larger in both size and weight and have a heavier bone and larger heads than females. They tend to be somewhat prouder and more territorial, and some people contend they're more courageous. The drawback is that they don't always get along well with other males. Many people find the males to be more dependent and affectionate. Intact (unneutered) males are apt to go off in search of females (of course, any dog should be securely fenced) and often think nothing of repeatedly lifting their legs on furniture to mark a house as their territory. Neutering the male before he is sexually mature will inhibit such ‘territorial’ linked behaviors like urine-marking and aggressive posturing.
Male dogs have genitals that are easy to see. When you roll them over to rub their belly, there's "something" in the way, and some owners feel self-conscious about that. Male dogs may also become aroused and/or lick their private parts, and again, some owners find this embarrassing, especially when Grandma happens to be visiting. When making trips outside for potty breaks a male dog may urinate in little spurts here and there, and it can seem to take him forever to relive himself. One advantage however, is that where they tend to relieve themselves typically won't kill the grass.
Females: The females are typically smaller. They may be a bit more level-headed, and they fight less with each other, but when they do fight, the battle can be ferocious, even to the death. Many people contend that the females are the ones they would want to protect them, and that the females are more intelligent. Their main drawback is that intact females come in estrus ("heat" / "season") twice or three times a year. This period lasts for around three weeks, during which time you must keep them away from neighborhood males who may consider your house a singles bar. You must also contend with her discharge and her possible attempts to elope with her suitors. Spaying your female will significantly reduce the incidence of mammary cancer if done before her first heat and of course totally prevents unwanted puppies. A female dog can hold her urine longer than a male. They can wait as long as 12 hours if necessary, which might be an advantage in a household where no one is home during the day. When going potty a female will usually empty her bladder all at once unlike the males. One downfall is that the urine may kill or stain your grass in the areas they choose to relive themselves.