RecruitingBiological interventionVaginal Microbiome Seeding and Health Outcomes in Cesarean-delivered Neonates.Neonates delivered by scheduled Cesarean Section will be randomized to receive vaginal seeding (exposing the infant to Mother's vaginal flora) or sham. Infants will be followed for three years to examine health outcomes including microbiome development, immune development, metabolic outcomes, and any adverse events.