ABSTRACT
Robert and Baylis evaluate the biology of species identity and the morality of crossing species boundaries in the context of emerging research that involves combining human and nonhuman animals at the genetic or cellular level. They review biological and philosophical problems of defining species as well as earlier attempts to forbid crossing species boundaries. While not attempting to establish the immorality of crossing species boundaries, they suggest that such crosses will result in important moral concerns and confusion about social and ethical obligations to novel interspecies beings.
