The present disclosure generally relates to personalized nutritional compositions for pediatric subjects, wherein the nutritional composition can include one of three distinct profiles of human milk oligosaccharides (HMOs). The present disclosure also relates to methods for determining the composition of HMOs present in or that would be present in the breast milk of the mother of a pediatric subject as determined by the mother's secretor status and/or Lewis blood group, and providing to the pediatric subject a nutritional composition comprising an HMO profile most similar to the HMOs present or that would be present in the breast milk of the subject's mother.