Project Summary/Abstract Our long-term goal is to foster genetically-informed reproductive health knowledge and behaviors among young adults with sickle cell disease (SCD) or sickle cell trait (SCT) with a web-based, tailored, multimedia intervention (CHOICES). In follow-up to genetic counseling, CHOICES helps them engage in behaviors concordant with their parenting plan. Developed with the sickle cell community, CHOICES is designed to help young adults with SCD or SCT gain knowledge of genetic inheritance, specify their preconception reproductive health intentions (their parenting plan), and engage in reproductive health behaviors concordant with their parenting plan. We found high acceptability of both the e-Book (usual care control) and CHOICES interventions. We also found sustained (24 mo), significant effects on knowledge but not on at behavior, presumably because 49% of the participants were not at risk of having a child with SCD (e.g., partner had normal hemoglobin, Hgb A). Of the participants at risk of having a child with SCD (at-risk) and who expressed intention to get pregnant soon and have a child free of SCD, the CHOICES group’s (n=26), behaviors showed a 27% relative at-risk time reduction compared to the e-Book group (n=16). However, the difference was not statistically significant given the small, underpowered sample (n=42). Hence, we propose an adequately powered RCT with the CHOICES intervention and an e-Book control to compare their effects on genetic inheritance knowledge and at-risk reproductive health behaviors (immediate posttest and at 6, 12, 18, & 24 mo). Using proven strategies (referrals, social media, and communication technology) for recruiting and retaining the sample, we will use web-based data collection (SCKnowIQ) and intervention delivery strategies enhanced by nudges and tailored boosters. In a sample of 430 adult men and women, aged 18-35 yr with SCD or SCT, at-risk, and planning within 2 years to have a child free of SCD, the specific aims are to: Aim 1. Compare e-Book and CHOICES groups for effects on (a) knowledge (primary endpoint), and (b) at-risk behavior (secondary endpoint) measured with the SCKnowIQ over time (baseline, post-test, 6,12, 18,24 mo). We hypothesize that across all time points post baseline, there will be (a) higher knowledge scores and (b) lower percentage of time with at-risk behaviors (at-risk time) in the CHOICES than in the e-Book groups. Aim 2. Explore the relationship between demographic factors (e.g., sex, SC status), intervention acceptability, and the Aim1 endpoints (knowledge, behavior). We will conduct subgroup analyses to provide insight into the baseline knowledge and behavior as well as the intervention effects in different demographic or acceptability groups. Given the scalability and low cost of CHOICES, if proved to be effective, it can reach the affected population at low cost. As a genetic counseling follow-up model, CHOICES may translate into informed parental decision...