"Newman has never made a humouse and says he probably never would. In fact, he and his patent partner, technology critic Jeremy Rifkin, have deep moral objections to manipulating human life and oppose patenting any living organisms. They believe that federal law does not sufficiently limit scientific work with human embryos and human life, and their humouse is intended to change just that.

Patent law does not require them to make a humouse, but they must show it can be done. Newman says he could take an embryo from one species, either man or mouse, and inject it with embryonic cells from the other species. The result would be an animal with cells from both species scattered throughout and working cooperatively. A similar technique was used in the early 1980s to make a sheep-goat hybrid, dubbed a "geep," though no one is known to have tried a similar cross-species mix with humans.

"There really is no boundary on what you can do with human life. There's no natural stopping point," Newman said. "That troubles me. I think it will ultimately lead to genetically engineered human beings made for sale."