Children have been termed therapeutic orphans due to the lack of adequate dosing information, age-appropriate formulations, and efficacy and safety information regarding prescribed drugs. The majority of drugs are still used in children off label. To improve knowledge in this field, Congress enacted The Best Pharmaceuticals for Children Act (BPCA) in 2002. BPCA was reauthorized in 2007, 2012, 2017, and 2022. The NICHD has the primary responsibility to administer, contract, and monitor studies that develop data for potential label modification that will benefit children. Through these studies a large number of biospecimens are generated. It is anticipated that samples in long term storage will be shared for secondary research. The Pediatric Trials Network is an NICHD-funded network that conducts clinical trials aimed at addressing goals of the BPCA. This Network generates rare biospecimens from children that are invaluable for advancing understanding of the effect of pharmaceuticals in children.