A new investigation at the Leiden University Medical Center (LUMC) has confirmed significant administrative errors within its sperm donor bank, including cases where donors’ identities were unknown for numerous offspring. The findings highlighted a failure to adhere to guidelines limiting donor offspring to prevent incest risks. Many affected individuals report feelings of betrayal. LUMC is advocating for a nationwide investigation into issues at more sperm banks after discovering that several donors fathered more than the permitted number of children.