In 2007, Ishola Agbaje, Deirdre Rogers, Carmel McVicar, Neil McClure, Albert Atkinson, Con Mallidis, and Sheena Lewis published “Insulin Dependent Diabetes Mellitus: Implications for Male Reproductive Function,” hereby “Diabetes Mellitus: Implications,” in the journal Human Reproduction. In their article, the authors explore the effects of elevated blood sugar in the form of diabetes mellitus on the quality of male sperm. When investigating possible fertility issues, fertility specialists often study semen, the male reproductive fluid that contains sperm cells to detect changes in sperm count, movement, and structure. In “Diabetes Mellitus: Implications,” the authors use both conventional semen analysis and technical molecular methods to assess the quality of sperm from diabetic and non-diabetic men. The authors found that men with diabetes had higher levels of DNA damage within their sperm and highlighted a need for additional research on the link between diabetes and male reproductive health.

In 2021, the World Health Organization, or WHO, published the sixth edition of their Laboratory Manual for the Examination and Processing of Human Semen, which provides standardized guidelines to physicians and other medical professionals performing semen analysis. Semen analysis is a technique that medical professionals use to analyze the characteristics of a male’s semen and sperm cells to identify possible causes of male infertility. A sperm cell is the male sex cell that fertilizes a female’s egg cell, while semen is the fluid containing sperm cells that men release during ejaculation. The WHO created the first laboratory manual for semen analysis in 1980, a time when there was no standardized way to analyze a male’s semen sample. The WHO laboratory manual was one of the first documents to standardize a procedure for evaluating human semen to look for sperm abnormalities, and it remains one of the most widespread methods of evaluating a male’s fertility potential and determining the causes of male infertility.

In December of 2016, Margus Punab and colleagues published “Causes of Male Infertility: A 9-year Prospective Monocentre Study on 1737 Patients with Reduced Total Sperm Counts,” hereafter “Male Infertility,” in the journal Human Reproduction. The study examines the main causes of severe male factor infertility, or SMF infertility, which occurs when a male’s semen has a very low number of healthy sperm cells or contains atypically low levels of sperm cells. In “Male Infertility,” the authors determine the primary cause of SMF infertility in forty percent of their participants, and among those participants, they found that the primary causes of SMF infertility were varicoceles, or enlarged veins within the loose bag of skin holding the testicles. The authors did not determine the cause of SMF infertility in the remaining sixty percent of the cases, noting a gap in the current understanding of the causes of SMF infertility. “Male Infertility” was one of the first large-scale studies to reveal certain underlying causes of SMF infertility, and its conclusions have allowed researchers to investigate fertility solutions for male patients who would otherwise not be able to reproduce.