Our aims for RC1-00137 entitled “Human Oocyte Development for Genetic, Pharmacological and Reprogramming Applications” are as follows: Aim 1) Assess and compare the potential of multiple nonfederal hESC lines to contribute to the germ cell lineage. Aim 2) Differentiate hESCs to oocytes. Aim 3) Assay the ability of differentiated germ cells to reprogram a somatic nucleus. In the last funding cycle, we have succeeded in extending our analysis of hESC lines and finished the first aim to compare the potential of multiple lines. In the second aim, we have made significant progress towards differentiating mature human germ cells (oocytes) and understanding the fundamentals of germ cell development that will contribute to futher success. Finally, as the field of human pluripotent stem cell research has advanced, it has become clear that there is a need to consider the potential importance of SCNT and the use of additional factors that function in the oocyte to embryo transition to improve line generation. In addressing our aims, we have made tremendous progress towards understanding basic and clinical properties of human germ cells through differentiation and maturation. The information will inform stem cell biology and as well as human reproductive health. We have published three manuscripts on this project, have several others in various stages of preparation/submission and have generated one application for intellectual property (patent).