Abstract The Motherhood Biographies and Midlife Women’s Health R01 project maps how divergence in motherhood experi- ences contributes to growing midlife health disparities. About 85 percent of midlife women today are mothers, but path- ways to motherhood—what we call motherhood biographies—are increasingly diverse across many dimensions relevant to health, including age at first birth and spacing of children. The parent project tests how motherhood biographies mat- ter for midlife women’s health with a specific focus on race/ethnicity and socioeconomic status. We compare mothers and non-mothers as well as mothers with differing motherhood biography profiles using nationally representative data from the 1979-2018 waves of the National Longitudinal Study of Youth (NLSY79; N=4,951 women). We are testing the following aims with this diversity supplement and Crutchfield’s efforts focused on Aims 2 and 3: AIM 1: Identify how motherhood biographies—including childlessness—relate to midlife health. AIM 2: Identify how the impact of mother- hood biographies on health depends on characteristics of child-mother relationship at midlife. AIM 3: Identify the heter- ogeneous effects by educational attainment and race/ethnicity of motherhood biographies on midlife health. Given Crutchfield’s research and career interests, the proposed supplemental project will be beneficial to all parties, as well as to the broader field of health disparities research across the life course. Crutchfield will specifically look at two questions that fall within the goals of the Parent R01’s Aims 2 and 3: (1) Do the dynamics/quality of mother-adult child relation- ships at midlife shape the impact of motherhood biographies on health outcomes at the intersection of socioeconomic status (SES) and race-ethnicity? and (2) Specifically among Black women, how does the impact of mother-adult child relationship dynamics/quality at midlife on the association between motherhood biographies and health differ by SES? Throughout the duration of the administrative supplement, which will be Crutchfield’s 4th and 5th years in the Doctoral program, she will work with the entire team to obtain training specifically on aging and life course theories and meth- ods;, take courses to advance her statistical training, especially related to longitudinal data analysis and causal inference methods;, conduct research for publications, presentations, and other research activities public scholarship; and receive career and professionalization training, including related to writing grants and applying for jobs in the aging and life course field. Life course training will include rigorous training in an interdisciplinary Aging Certificate at Ohio State; sta- tistical training will focus on course work on longitudinal data analysis and other life course methods. In addition, in Y2 of the grant (year 5 of her doctoral training), the entire mentorship team will also assist Crutchfield in developing an ag- ing-rela...