Controversies surrounding the 2010 world health organization cutoff values for human semen characteristics and its impact on unexplained infertility

Abstract

In 2010, the World Health Organization (WHO) published new reference criteria for human semen characteristics. Important methodological issues, including patient selection and methods for semen assessments, elucidate why reference values are markedly lower than those earlier reported. The validity of the new criteria as a representation of the semen quality of fertile men has been questioned as they have been generated from a small group of recent fathers of restricted geographic regions. The 2010 WHO criteria are likely to have a significant clinical effect as more men will be classified as having unexplained male infertility. This may lead to a deferment of referral and could delay the definitive diagnosis and management of the infertile couple. Due to the several inherent limitations of semen analysis as a surrogate marker of male infertility, physicians should exercise caution when interpreting results. Semen analysis alone is usually insufficient for the diagnosis, as it does not account for sperm dysfunction, such as immature chromatin, oxidative stress (OS), and DNA damage. A male infertility evaluation must go far beyond a simple semen analysis, as it has to be complemented with a proper physical examination, a comprehensive history taking, and relevant endocrine, genetic, and other investigations.