I totally agree with Red. One of the biggest deciding factors as to whether a breeder is "reputable" or not, is how much they care for the puppies that they chose to bring into the world. If they will pawn them off to a pet store to make quick cash, a pet store that doesn't care who you are or what you'll be doing with the pup as long as you pay, there are not only irreputable - they're a very sick, careless, uneducated human being!
Keeping that in mind - what are the chances that the puppy you get from a pet store will be mentally healthy (not even getting into the disease, malnourishment, dehydration, etc, that runs rampant in even "nice" looking pet stores)? What are the chances that they do not carry crippling genetic disorders? Very, very low. You're considerably lucky if they don't. Any breeder who sells puppies to a pet store obviously does not care about where those pups are going... so it's clear that they didn't care about giving those puppies the best care & socialization in their first few essential weeks of life... and therefore it can be assumed that they didn't care about tending to the mother during pregnancy, or before pregnancy, or choosing a great stud, or health screening, OR that they will give a crap about the next litter they pump out. So, this vicious cycle rages on. Some breeders who sell to pet stores might be slightly more ethical than others, but it's all a bunch of irresponsible people who do not care about the puppies they produce nor do they care enough to meet the new owners. Buying from a pet store is a complete and total risk and shows extreme disregard for the dog population & the unknown negligence toward that puppies parents/siblings/relatives in general.
