Genetic engineering often generates fear of out of control scientists creating Frankenstein creatures that will terrorize the general populace, especially in the cases of human-animal chimeras. While sometimes an accurate characterization of some researchers, this belief is often the result of repugnance for new technology rather than being rationally justified. To facilitate thoughtful discussion the moral issues raised by human-animal chimeras, ethicists and other stakeholders must develop a rational ethical framework before raw emotion has a chance of becoming the dominating justification for public opinion and policy. Derek Parfit’s work on lives worth living for human beings can provide valuable insight into the morality of creating chimeras. As long as their lives are overall good, then bringing them into existence does not harm them even if they are used for medical research or procedures, or they are created to carry on the homo sapiens’ “family” line.