Male or female? Which breed is suitable?

This will depends upon one‘s liking, reasons for having a dog, facilities available and even own personality. If you need a small-sized dog, choose a Spaniel, Pomerarian, Spitz, Apso, Pug, Dachshund or a Miniature Pinscher. If you want to go in for a medium sized laid-back gentle dog with comparatively low level activity, Retrievers are best suited for you. If you prefer playful hyper dogs, a Boxer, Dalmation, Pointer or a Dobermann will fit the bill. On the other hand, if you want a dog that will also protect you, your family and property, you can go in for a Dobermann, Rottweiler, any Mastiff, Boxer or a German Shepherd. Working Group breeds have an edge over other breeds for protection work but all dogs need to be trained for effective guard duties. Rottweilers and Dobermann are however known to be instinctively protective and make excellent guard dogs. Then there are Hounds and Gun Dogs for the sporting kind.

Having chosen the breed, one needs to decide whether to have a dog or a bitch. The following inputs can help:
Dogs are bigger in size, stronger, have ego problems, need firm handling and are generally more aggressive.
Bitches are smaller in size, easier to handle, normally more loving especially towards young children and come into season every six months unless spayed.
If you are keeping a dog for the first time, it is better to bring home a female puppy.
In case you already have a dog and want to add another, the problem is simple, for if you have a male, the choice would normally be a female and vice versa. But it is very much possible to have two males or females in the house provided you are familiar with the basic dog psychology and have sufficient experience in training and handling dogs. It is interesting to note that no dog likes to be at his own and almost every adult who is alone will welcome a pup of any sex/breed.