Chromosome studies in 496 infertile males with a sperm count below 10 million/ml.

Chromosome studies were performed on 106 men with azoospermia and 390 men with oligozoospermia (consistent sperm count below 10 million/ml). Constitutional chromosome abnormalities were found in 14.1% of the azoospermia group and in 5.1% of the oligozoospermia group. An overall incidence of 7.1% constitutional abnormalities indicates that this criterion of selection may be advisable for routine chromosome analysis of infertile men. A reduction of 25% in the workload increases the yield of chromosome abnormalities in the group of infertile men to 10-14 times above that expected in the normal population.