That would depend on the type of pet store you are talking about. There are the shops that in the business of selling animals - like dogs and cats. Then there are pet supply stores (like Petsmart) that are in the business of selling supplies. These stores often work together with a local shelter or animal welfare group, using the store space to showcase animals available for adoption. My local Petsmart does this with the Nothern Virginia Animal Rescue League. These cats and dogs are not bred for the purpose of retail. The are rescued and/or homeless animals that are in need of a home. In this case, the money you pay for the adoption DOES go toward the care/medical needs of the animals. Traditional pet shops get their animals from breeders (mills) who mass produce animals for the purpose of retail. These animals often have serious medical problems. This is why I say don't support traditional pet shops.