Well that's too bad, I assume the parents have not been screened for genetic diseases and malformities they could pass on to their offspring? I also assume they have not have any sort of temperament evaluation to prove that they are stable or have the proper temperament for their breed?
So basically you'll be making puppies that are the same quality as shelter pups? We know nothing about their health or temperament, great, that's just what the world needs. Instead of people getting shelter quality pups from a shelter where they would be saving their life, they are gonna get shelter quality pups from you. It'd be one thing if you were producing pups that had some qualities that made them harder to find than a shelter pup, like parents and grandparents free from genetic abnormalities so we have a pretty good feeling we're getting a healthy pup, a family history of therapy dogs so we know they have good temperaments (just because the parents are "nice" doesn't mean the grandparents were'nt absolutely viscious, and being a nice family pet doesn't mean the dog does well under stress), or parents who do some sort of job (like border collies who herd and labs who actually go out and hunt, hounds that hunt and track, etc.) so we know they have the temperament that the breed is supposed to have.
Nope your pups are just as likely as a shelter pup to grow up to be fearful, have terrible health, and act nothing like the breed should (I don't know what breed you have or I'd be more specific).
I don't mean to sound like a jerk, not at all. And you already said we shouldn't talk you out of it so I don't know why I bother, but this really gets on my nerves. We have millions of dogs getting killed each year in shelters and you are just going to make more of those dogs. In three years when one of the puppy's owners can't keep him anymore are you going to require that dog be given back to you? Or is he just going to fill up a spot in the shelter? how are you going to feel if in two years one of the dogs you produced has to be put down because he's in terrible pain from a disease on of the parents passed on to him? Or if in a few years one of the dogs attacks a child in his new family because he has a terrible temperament passed on from one of his long lost relatives? It very well may not happen, but it very well may. And it all could have been prevented.
I probably should have just kept my mouth shut but it's "breeders" like your parents that are the reason we have so many dogs in shelters. Good breeders require their dogs come back to them if they can't be kept, no matter how long they have been with their new families. Yeah mills contribute some, but I bet average joe breeders' dogs make up far more of the shelter population than mill's dogs.
In any case I suppose it's your parent's decision, no point in getting upset with you. I am sorry if I hurt your feelings, it was not my intention, but bringing these completely dependent lives into the world is not something you just do because pups are cute or fun. They grow up, they can have terrible health, terrible temperaments, and terrible lives. It's the breeder's job to make sure that doesn't happen, and it's prevented long before the breeding takes place.
If you really like pups consider fostering pregnant dogs (or cats if you like them too)for your local shelters or rescues, that way you can do it over and over again and the responsibility afterwards will fall on the rescue, not you. Plus you'd be saving lives, not killing them.