Among the exciting, leading edge research projects being carried out at New York Weill Cornell's Center for Reproductive Medicine and Infertility is the unprecedented identification and isolation of human spermatogenic cells (young sperm cells) from men with testicular failure and azoospermia. Sperm can be recovered from the tissue of a testicular biopsy and then prepared for use with intracytoplasmic sperm injection (ICSI) in in vitro fertilization (IVF). IVF with ICSI is the treatment of choice for male factor infertility and allows the achievement of pregnancies with sperm from subfertile men who are unable to conceive by standard IVF methods. The close collaboration of the Center's reproductive endocrinologists and infertility specialists with urologists from New York Weill Cornell's Center for Male Reproduction and Microsurgery yields outstanding results in the arena of male factor infertility. In fact, the first pregnancies after sperm retrieval for testicular failure were reported by New York Weill Cornell Center and their published results are among the highest in the world.