An infant had short limbs. His trunk was normally proportioned, but his head was slightly larger than normal. Both parents had normal limbs and these problems had never occurred in either of their...

An infant had short limbs. His trunk was normally proportioned, but his head was slightly larger than normal. Both parents had normal limbs and these problems had never occurred in either of their families. Could the mother’s ingestion of drugs during pregnancy have caused these abnormalities? If not, what would be the probable cause of these skeletal disorders? Could they occur again if the couple had more children?