Teacup pugs are not a separate or recognized breed. Teacup pugs are the result of breeding small pugs so that this genetic defect is carried on to produce even smaller pugs. While they can be cute, dwarfism is not a desirable trait in any breed, and should be eliminated.
The pug is one of the oldest dog breeds in the world. This dog is a favorite pet due to its cute looks. They are said to have Oriental origins and were a favorite among the Buddhist Monks as well as the Chinese. By the 16th century they made their way to Western Europe. Soon, they became a favorite dog breed among the European royals and by the year 1885, the American Kennel Club recognized it as a distinct breed. Male pugs are around 12 - 14 inches in height, while female pugs are 10 - 12 inches in height. Although they are the largest dogs in the toy breed category, they are still small in size.

General Information
You must have come across many advertisements that say, 'Teacup Pug for Sale'. You are tempted to bring home a pug that can fit in your tea-cup! Understand that teacups are not separate breeds. The term 'teacup' is used to refer to the size of these dogs. You won't have to worry about lack of space to keep a dog and the cute little pup will keep your kids entertained. If these are the reasons you want to get a teacup pug, it is better that before going ahead you obtain some more information about them.

Similar to pugs, teacup pugs are compact, muscular dogs with square features. They have a heavily wrinkled face with a black, snub-nosed snout. These dogs have an even temperament and are very friendly in nature. Pug puppies as well as adults are very playful and love to 'box' their toys with their feet. They do not require a lot of exercise and a short daily walk, with some light playtime at home, is enough for them. Their wrinkles need frequent cleaning to prevent the accumulation of dirt in them. Also, daily brushing of the coat will help keep shedding to a minimum, and keep it clean and sleek. A bit stubborn by nature, pugs demand patience while being trained. Pug owners need to be alert with the puppies as well as adults, since their miniature size makes them vulnerable to choking on something, get stamped on or getting seriously injured if dropped or while jumping from heights.

Purebred pugs are those whose parents fit the description provided by the AKC, and have been bred in a manner so as to remove any genetic faults. Thus, in purebred pugs health concerns are minimum. But if the parent pugs are defective in any way, then the litter will not be termed as purebred.

Half-breeds
Teacup pugs, as explained before, are obtained by mating two genetically defective parent pugs. They are half breeds. Instead of eliminating the undesirable dwarfism quality, these are bred to promote it, giving rise to a slew of health issues. These pugs are also called toy pugs, miniature pugs, mini pugs or micro mini pugs. They are so tiny that they can easily fit into tea cups. This fact is always highlighted by irresponsible breeders to sell them off to unwary customers. These pugs are actually called 'runt' by many breeders. They are smaller than their litter mates and are always weaker.

Cross-breeds
Crossbred teacup pugs are also half breeds. They are half breeds obtained by crossing a Chihuahua and a half bred Pug. They look pretty similar to the real deal, except for a slightly longer snout, and slightly thinner legs. These teacup puppies are not recognized by the AKC as well as other respective kennel clubs. Even a full-grown teacup pug will be the size of a puppy all its life.
Is it the Right Choice?
There are a number of issues that you will need to address when bringing a teacup pug home as a pet. You may enjoy the miniature version as pet, but be ready for a number of visits to the vet. As already mentioned, a teacup pug is the 'runt' of the litter or a crossbred pup. It is very small in size and plagued with a number of health problems. These pugs often suffer from hypoglycemia, knee and hip problems, brain defects, kidney problems, heart ailments, brittle bones, skin disorders, and many more. These teacup versions are pretty fragile and can be easily injured and even killed. They are small enough to be vulnerable to being stamped upon or dying under the weight of some heavy object falling over them. They are not a good choice of pet for children under 8 years of age. They may handle the pug roughly or may not understand the correct way of caring for these pugs. This can lead to severe injuries and bone joint dislocation in the pug.

Another major problem with these tiny pugs is their ability to produce a litter. Their tiny size makes it very difficult for them to deliver, making natural delivery almost impossible. Natural birthing will come with serious health risks to the mother. Hence, a C-section is required to deliver the litter. Which can be tedious as it means more vet visits, steep fees, and lots of extra care and attention. It can be difficult to handle if you are not prepared for so much responsibility.
As you can see, a teacup pug will have a life full of woes. Teacup pugs may prove to be great pets, but you will have to invest quite a bit of extra attention and care regarding its safety. It is the weaker one of its litter and, therefore, more prone to health complications. Many people are interested in teacup breeds, but forget that they are encouraging breeders to breed these weak dogs. If you own a teacup pug, do take care of its health, even if you find it comparatively healthy.