Somatic and meiotic chromosomes have been studied prospectively in 200 subfertile males. The results have been correlated with clinical, seminal and endocrinological features, with histological findings in testicular biopsies and with response to conventional treatment.

Somatic chromosome abnormalities were found in 3·5% of cases and variants of the Y chromosome were found in 10·5 %. Definite abnormalities in meiotic chromosomes were observed in 20% of these patients, including supernumerary chromosomes, low chiasma frequency and asynapsis, and translocations. Many of these abnormalities occurred as mosaics, presumably a result of meiotic mutation. In 4 cases, a previously unrecognised abnormality in pachynemas has been defined. Absence of meiosis was found in 12% of cases, which correlated well with the histological findings of germinal cell aplasia and elevated urinary FSH levels.

It is concluded from this preliminary analysis that abnormalities in meiosis may account for the decreased spermatogenesis and poor response to treatment in at least 20% of subfertile men. However, these abnormalities do not constitute a contra-indication to treatment as normal pregnancies can still be produced, in a few cases albeit, sometimes requiring monitoring.