Though their justification is environmental rather than animal, researchers at Utrecht University in the Netherlands are trying to grow meat in a lab, raising the possibility of a carnivorous diet disconnected from killing.

Asked whether people would be repulsed by lab-grown meat, Roelen said he believed there would be enough demand, as much of what people eat today is already extensively processed, from the feed that animals consume to the conditions under which they are raised and the preparation of meat after slaughter.