The NICHD Population Research Core Grant operates within the Laboratories for Reproductive Biology to promote interdisciplinary research on the control of reproduction leading to better methods for contraception and for treatment of reproductive disorders. Major emphasis has been placed on the male. A broad range of research centering on molecular mechanisms regulating male reproductive functions has been brought together in The Laboratories for Reproductive Biology within the areas of reproductive neuroendocrinology, regulation of gonadal function, sperm maturation, fertilization and implantation. The shared Core Facilities included in the P-30 population center provide recombinant DNA, tissue culture, histochemistry-microscopy, radioimmunoassay, peptide synthesis/sequencing, transgenic mouse, and administrative services. In addition to enhancing the productivity, quality and cost effectiveness of research, the Cores nurture interdisciplinary collaboration among reproductive scientists and facilitate technical training within The Laboratories for Reproductive Biology. Eligibility for core use is requested for 33 funded research projects.