Approach to the patient with oligozoospermia.

Male infertility affects 1 in 20 men and is the sole or contributory factor in half of assisted reproductive treatments (ARTs). A reduced sperm density (oligozoospermia) is often accompanied by poor motility and morphology reflecting qualitative and quantitative defects in spermatogenesis. Many reproductive and nonreproductive disorders and treatments may be responsible, but most cases remain unexplained (idiopathic). A thorough evaluation may identify treatable causes and allow natural fertility. Comorbidities more prevalent in infertile men, especially androgen deficiency and testicular cancer, should be sought. Idiopathic spermatogenic disorders are common, but evidence-based treatment is not available; full evaluation informs management and the decision to pursue ART using the low numbers of functional sperm available. Chromosomal anomalies may impact the chance of a normal healthy pregnancy, and new genetic causes of oligozoospermia are being discovered. ART, particularly intracytoplasmic sperm injection, bypasses instead of treats the sperm defect but has dramatically improved the fertility prospects. The clinical approach to the oligozoospermic man involves understanding reproductive endocrinology, aspects of urology and clinical genetics, modern ART options, and the realistic discussion of their outcomes, alternatives such as adoption or donor gametes, and appreciation of the psychosocial concerns of the couple.