A newly discovered genetic defect that causes a form of intellectual/developmental disability (I/DD) can now be included in genetic screenings to confirm a diagnosis and aid familial risk assessment. The defect causes ‘X-linked syndromal intellectual disability’ (XLID). The condition causes symptoms only in males; it can lead to behavioral issues, stunted growth, and smaller than average brains and testes. About 3% of people worldwide have XLID, which is caused by defects/mutations in over 140 different genes. Women with X-linked gene defects have a 50% chance of passing it on to their children. Male children with . . .