Puzzle, Brainteaser

The owner of a pet shop is trying to persuade two mothers and two daughters, who entered the store together, to buy the three kittens in the display window. He made the sale. Each customer left the store with her own pet kitten. None of them shared a kitten. There were no other kittens in the shop except these three. How can three kittens be owned by two mothers and two daughters so that each has her own individual pet?