Published online by Cambridge University Press: 01 July 1999
Approximately 30–40% of couples seeking fertility treatments have male factor infertility. Their dysfunctions include azoospermia, oligozoospermia, asthenozoospermia and teratozoospermia. Those with azoospermia represent about 25% of the total, and of these about 30% have an obstructive process while the remaining have either primary or secondary testicular failure. In the obstructive azoospermia group, 25% of males have congenital bilateral absence of the vas deferens (CBAVD).