Embryonic stem cell research has proved enormously controversial in the United States and in other nations such as Germany, France, and Japan. For the most part, the controversy over stem cell research has hinged on the morality of destroying human embryos to obtain stem cells to culture cell lines for research purposes. Some think that an embryo is a human being from the moment of conception, with full moral standing and rights. Others argue that whereas human embryos may have some moral standing, their moral status does not preclude their destruction for a moral purpose such as clinical research aimed at the treatment of severely disabling or fatal diseases.