Clinical and meiotic studies were done on an infertile man with a translocation between Yq and 13q, who was identified through the birth of his son with partial trisomy 13q. Seminal plasma transferrin showed preserved Sertoli cell function while lactate dehydrogenase C4 indicated hypospermatogenesis. A quadrivalent in diakinesis and spermatogenic arrest in the second meiotic division was detected.