At least 50% of couples referred for infertility investigation and treatment are found to have a contributing male factor. Male factor infertility can represent a variety of defects, which result in abnormal sperm number, morphology or function. Detailed analysis of sperm assessment and function are important for accurate diagnosis, and are described in detail in numerous textbooks of practical andrology and semen analysis. A comprehensive review of semen analysis is beyong the scope of this book, and only details relevant to assisted conception treatment will be described here.

The World Health Organization (WHO) laboratory manual describes standard conditions for the collection of semen samples, their delivery and the standardization of laboratory assessment procedures. The WHO standards indicate that a ‘normal’ semen sample contains at least 20×106 spermatozoa/ ml, with at least 50% exhibiting good to excellent forward progressive movement within 60 minutes after ejaculation. The introduction of external quality control and quality assurance schemes in semen assessment have highlighted the fact that accurate analysis of seminal fluid is notoriously difficult to standardize, with many technical variables, and the quality of semen analysis in different laboratories can be highly variable (Matson, 1995). This implies that diagnosis and treatment modality chosen for a patient could differ according to the laboratory carrying out the assessment.