The Training Program in Reproductive, Perinatal, and Pediatric Life Course Epidemiology - Program Summary: This is a competitive renewal application for our Training Program in Reproductive, Perinatal, and Pediatric (RPP) Life Course Epidemiology – sponsored by the Departments of Epidemiology, Social and Behavioral Sciences, and Biostatistics at the Harvard T.H. Chan School of Public Health. The Program is further supported by the departments of Environmental Health, Nutrition, and Immunology and Infectious Diseases, reflecting the transdisciplinary nature of RPP life course epidemiology. Over the next five years, we aim to build on earlier successes and further develop the program by adding new faculty, increasing access to campus resources, expanding training in clinical trials, and implementing mentor training to prepare the next generation of life course-focused, innovative investigators. The Program includes accomplished faculty who have collaborated to advance understanding of critical issues in RPP research. The goals of the Program are to train pre- and postdoctoral fellows to become future leading scholars who are: 1) knowledgeable about the current state of science in RPP life course epidemiology; 2) skilled in advanced epidemiological and biostatistical methods including causal inference and artificial intelligence; 3) skilled in communication, with the ability to craft research proposals and manuscripts, and to interpret and disseminate results to scientific and lay communities; and 4) anchored in peer and professional networks that support continuous professional development, leadership, teamwork, and access to resources to translate knowledge into new independent RPP research. The Program aims not only to develop knowledge, skills, and capacity for scientific excellence in RPP sciences, but also to inspire young scholars to adapt to evolving research needs, which will increasingly require a transdisciplinary, team-science approach to tackle contemporary and future public health issues. Thus, fellows will follow transdisciplinary training involving coursework, seminars, practicum, and independent and collaborative research in RPP. A key aspect of this application is a cutting-edge mentoring and mentor training plan, assigning at least two mentors from different career stages with expertise in the fellow’s research area. Each fellow will gain hands-on experience with study planning, data collection, and analysis in a rich training environment leveraging established cohorts led by Program Faculty, with additional mentoring in grantsmanship, publishing, teaching, public speaking, leadership, and citizenship to bridge toward launching independent RPP research careers. Aligned with the NICHD mission, this Program will build capacity for a scientific workforce equipped to advance understanding of reproductive, perinatal, and pediatric health issues, and use cutting-edge evidence to inform clinical practice, clinical trials, translate science into policy action, and implement prevention strategies to improve health across the reproductive life course.