The scientific pillars of development and regenerative medicine research are reproduction, transgenesis, and cloning of stem and progenitor cells using diverse animal models. Assisted Reproductive Technology (ART) is vital to ensure that the most innovative infertility therapies are as safe and effective as possible. The combination of transgenics and cloning may result in the generation of identical sets of disease models. Understanding the therapeutic potentials of nonhuman stem cells provides a more solid scientific foundation for the ethical and social conversations regarding human embryonic stem (ES) cells. Researchers in this group accelerate discoveries on stem cell potentials, and utilize diverse models, including worms, mice, and primates, to assess adipogenesis, reproductive aging, germ cell differentiation, and infertility.