Project Summary: This R25 application seeks five years of sponsorship for our advanced training course entitled: Frontiers in Reproduction (FIR), held annually at the MBL in Woods Hole under the Directorship of Dr. Rafael A. Fissore (UMass, Amherst). The course is directed towards advanced graduate students, post-doctoral fellows, and physician-scientists who are committed to fundamental, translational or clinical research studies in the field of reproductive biology. FIR introduces participating trainees to state-of-the-art research in the field, spanning reproductive endocrinology, germ cell and organ development, gametogenesis and implantation and placentation, and Assisted Reproductive Technologies (ART). We provide trainees with fundamental concepts, knowledge of “cutting edge” research and laboratory techniques, career mentoring and instruction in the ethical, legal, and societal impact of research in reproduction. To achieve this goal, we propose the following specific aims: 1) Provide a coherent series of lectures covering fundamental concepts spanning the broad field of reproductive biology and introducing students to the open questions in the field. 2) Provide lectures and discussions on the emerging concepts and techniques in ART and its applications. 3) Train students in advanced cellular and molecular techniques required to probe the cellular and organ function underlying reproduction through state-of-the-art and hands-on demonstrations and mini-projects. 4) Provide opportunities for career planning and advancement by offering training on scientific communication, data analysis, and oral presentations. 5) Educate trainees on the ethical considerations involved in the use of human and animals, and on the use of animals as research models. 6) Foster a diverse, collegial environment that leads to long-term mentorship relationships and collaborations among trainees and between students and faculty. FIR is divided into three topical scientific sections, each lasting 2 weeks. The course meets 5-6 days a week with 2 daily lectures and hands-on laboratory exercises. FIR continually incorporates new faculty, topics and technological breakthroughs to ensure that the training remains at the forefront of the field. The course will provide a significant benefit to biomedical research through the training of new investigators in the field of reproductive biology and biotechnology, and ART. Reproductive science is a broad and well-established field with enormous impact in society and with biomedical implications across the entire spectrum of NIH’s portfolios.