in the late 2030s, it became popular (and was subsequently legalized) for humans to undergo genetic sequencing, changing their DNA sequences to alter different aspects of themselves. some looked to become smarter, stronger, prettier — others looked to more esoteric changes. by far one of the most exotic operations was adding animalistic features to the body; canine or feline ears atop the head, tails, claws, paws, anything and everything you could want.
due to the mechanism of these changes, the alterations persisted through generations, and soon the line between the human race and the rest of the animal kingdom started to blur.