As an owner, you are responsible for spaying your female dog to ensure that you are not inundated with littler of pups for whom it will be difficult, if not impossible, to find good homes.
A female dog can breed at least twice a year and may produce anything from two to fifteen pups. Small breeds like pom-peks usually have small litters but big ones, like German Shepherds, can produced up to 15 pups each time.
In a few years, assuming that half the pups in each litter are female and continue to breed unchecked, one dog can have thousands of descendents.
It is your job, as a responsible owner, to make sure that this does not happen.
It is no use saying “Oh, we can always find homes for the pups.” Perhaps you can, but do you know what is going to happen to those pups later? They may not be well treated, they may end up as strays on the road and, in many cases, they will surely continue to breed unchecked.