Male infertility is the sole or contributory cause of infertility in half of all couples. Good clinical practice demands evaluation of the male partner, as it may identify reversible or treatable conditions (e.g. gonadotrophin deficiency) and prevalent co-morbidities (e.g. testosterone deficiency, testis cancer).
Primary spermatogenic failure is the most common diagnosis, encompassing diverse pathogenic processes resulting in reduced sperm number, motility, morphology and/or function. A cause is evident in a minority, such as genetic defects (karyotypic anomalies, Y chromosomal microdeletions) or testicular damage from vascular, chemo/radiotherapy or infective agents. However, most are unexplained (idiopathic). Medical interventions for idiopathic infertility often lack an evidence base. Obstruction is the second most common of azoospermia, notably post-vasectomy or due to bilateral congenital absence of the vas that is associated with cystic fibrosis gene defects
Assisted reproductive treatments (ART), particularly intracytoplasmic sperm injection (ICSI), allow fertility in many otherwise untreatable male factor couples. ICSI is widely used and offers excellent fertility prospects with poor quality ejaculated or testicular/epididymal sperm. In azoospermic men with severe spermatogenic failure, sperm isolation is possible in 30-60% of cases, including post-chemotherapy or in Klinefelter’s syndrome (wherein most sperm are euploid). Microsurgical dissection as opposed to random biopsy improve recovery rates.
A modestly increased rate of congenital malformations and karyotypic anomalies in IVF/ICSI offspring is recognised. Overall data on the health and development of IVF-conceived adult offspring is reassuring. However, data on the health outcomes of ICSI offspring for specific types of male infertility is extremely limited. Aside from Y microdeletions, the risk of vertical transmission of the male infertility phenotype via ICSI is unclear, however but subnormal semen quality appears more frequent in offspring. Follow up studies are ongoing and in future databases must include more data on male etiology.