Strictly speaking, man can’t make a cat. (Only God—or nature—can do that.) But by mating one type of cat with another, humans can create an entirely new type of cat. A female cat of breed X mates with a male cat of breed Y, and their kittens are the new breed, Z. A “man-made” breed results from this deliberate hybridizing.
Once the new breed is established, of course, new litters can be produced by mating the hybrids with other hybrids, instead of reproducing the original mating of breed X with breed Y. As you will see in later entries, many of the newer breeds are man-made.