of Cell, Developmental, and Regenerative Biology at the Icahn School of Medicine at Mount Sinai since 1996 (Chairman 2000-2007).
His laboratory identified and characterised proteins that make up the zona pellucida (ZP) of mammalian eggs and determined their role in fertilisation.
His main research contributions lie in the areas of mammalian oogenesis and fertilization, particularly on the structure and function of the egg's ZP.
[citation needed] He has been an advisor to NIH, NSF, ERC, NSC, WHO, Wellcome Trust, Schering AG, and Hoffmann-La Roche and delivered the Helen Mangelsdorph, M.C.
Chang, James E. Leatham, Ernst Schering, Alan S. Parkes, and Luigi Mastroianni memorial lectures.