Pediatric clinical research is currently constrained by limited access to comprehensive, high quality, real-world data. This issue is especially pressing in the case of rare and complex diseases, where small patient populations are distributed across multiple countries. Traditional data-sharing models face increasing legal and logistical challenges, particularly under strict data protection regulations such as the General Data Protection Regulation (GDPR). Federated Data Networks (FDNs) offer a compelling solution to this challenge, enabling cross-border and cross-institutional research collaboration while preserving data privacy and institutional control.