I am a Doberman breeder (on a very limited basis, like one litter every 2 or 3 years.) I just wanted to add a couple of things...
First, Min-Pins are Miniature German Pinschers, instead of Miniature Dobermans. They are related, since Pinshcers are one of the breeds used to create the Doberman, but not that closely related.
Hopefully you will take back any of these puppies at any point in their lives, if they need to be rehomed for any reason. That's really what separates the 'responsible' breeders from those that are just selling puppies (even though you probably gave yours away.)
Whenever dogs are bred, people should be aware of issues related to structure, temperament, and health. If the dogs are not 'sound' in all 3 areas, they should not be bred. Anyone buying a dog should look for proof of health and probably temperament testing, depending on the breed. For instance, the parents of my Doberman litter had their hips x-rayed (OFAd), thyroid and liver tests, vwd/bleeding disorder test, heart test, etc. They've also both taken two different temperament tests. There's a lot more to breeding dogs than just getting two Dobermans or two Poodles or whatever and breeding them. Obviously don't EVER buy a dog from a pet shop or puppy mill/irresponsible breeder. In general, the quality animals produced by responsible, ethical breeders are not the same ones populating the local shelters. It is hard on a female dog to have and raise a litter of puppies, and no ethical breeders breed more than once per year or usually 3 litters in a lifetime (and not before 2 years of age at least.)
1.3 Dobermans (1 female is spayed)