To report on a male patient with complete deletion of azoospermia factor b (AZFb) who presented with severe oligoasthenozoospermia, but who successfully fathered a child via intracytoplasmic sperm injection (ICSI).

Karyotype analysis of peripheral blood lymphocytes was performed by standard G-banding. Y chromosome microdeletions were detected by multiplex polymerase chain reaction amplification using AZF-specific, sequence-tagged site markers. The ICSI procedure was performed using ejaculated motile spermatozoa.

Cytogenetic analysis of the patient revealed a normal male karyotype, 46,XY. Multiplex polymerase chain reaction screening showed complete deletion of AZFb demonstrated by the absence of specific sequence-tagged site markers sY121, sY127, sY134, and sY143. Following successful ICSI, an ultrasound scan of the patient's partner revealed a single pregnancy with cardiac activity. A healthy boy was born by cesarean section at 38 weeks of gestation. Genetic testing 2 years later revealed that the infant had inherited his father's AZFb deletion.

Evidence from this case supports the fact that carriers of AZFb deletions can sometimes produce spermatozoa and father a son with the same AZFb deletion. This possibility reinforces the need for genetic counseling in patients with Y chromosome microdeletions.