Chihuahuas can mate as soon as they are sexually active, but a responsible breeder will wait to start breeding his or her Chihuahuas until they have reached full sexual maturity at 12 to 15 months for males and 6 to 18 months for females, says the AKC. Some female dogs can take as long as two years to reach full sexual maturity; however, the AKC also cautions that females should never be bred during their first heat cycle.
Before breeding, it is important that the female dog be brought in for a pre-breeding physical examination. At this time, the dog's shots should be updated if needed and the dog should be tested for possible parasites. The female dog should not be overweight before being bred and should have a stable temperament. Without a stable temperament and a more mature demeanor, the dog will often be a poor mother. Males should also be healthy.
The Chihuahua is a tiny dog and is considered the world's smallest dog at 3 to 6 pounds, writes the Dog Channel. The dog comes in a smooth coat or a long coat as well as multiple colors. Anyone thinking of breeding the dogs should remember that due to their size, it is best to keep them away from young children and even adolescents who are unaware of the fragility of the dog.