Male infertility refers to the inability to impregnate a fertile female due to abnormalities in the quantity and quality of sperm. In about 1 in 5 couples, infertility issues come from the male partner (Andrology Australia, 2018).

Industrial Chemicals and Heavy Metals

Low sperm counts can result from extended exposure to chemicals such as benzenes, toluene, pesticides, herbicides, organic solvents, painting materials and heavy metals such as lead (Mayo Clinic, n.d.). For example, male mechanics exposed to trichloroethylene (TCE), a chemical used as a degreasing agent, were found to have TCE and its by-products in their semen. A study conducted on mice found that TCE exposure led to reproductive tissue damage, suggesting that TCE is metabolized in the human reproductive tract and can adversely affect the normal development of sperm (Xu et al., 2004).

Radiation or X-rays

Sperm production may be reduced as a result of exposure to radiation. With low doses, sperm counts are able to eventually return back to normal. However, high doses of radiation may lead to permanent sperm production reduction (Mayo Clinic, n.d.).

Overheating of Testicles

Sperm production and function will be become impaired at elevated temperatures. Sitting, wearing tight clothing, and using a laptop for long periods of time may contribute to the increased temperature in the scrotum and thus have the ability to reduce sperm production (Mayo Clinic, n.d.)

Drug use

Anabolic-androgenic steroids are one of the most common substances known to contribute to male infertility. They are also known as performance-enhancing drugs and are typically taken by athletes to increase muscle mass and strength. This type of drug can result in a shrinkage of testicles and a decrease in sperm production (Mayo Clinic, n.d.).

Alcohol Use

Alcohol has the ability to disturb the feedback mechanisms of the hypothalamus-pituitary-gonadal (HPG) axis. This can result in reduced or impaired production of hormones involved in sperm production such as luteinizing hormone (LH) and follicle-stimulating hormone (FSH). Alcohol consumption can also lower testosterone levels (Gude, 2012). All these factors contribute to decreased sperm production in addition to erectile dysfunction (Mayo Clinic, n.d.).

Smoking

It is suggested that the nicotine found in cigarette smoke contributes to significant decreases in sperm motility and sperm count. These effects can be reversed with cessation of smoking (Kovac et al., 2015). Secondhand smoking will contribute to male infertility as well (Mayo Clinic, n.d.).

Emotional/Psychological Stress

Severe or prolonged psychological stress such as depression, lack of self-esteem, stigma, grief, and isolation could reduce sperm count, libido, contribute to erectile dysfunction, and delayed or inhibited ejaculation (Basu, 2014). In addition, stress can interfere with certain hormones needed to produce sperm. Kirby et al. found that stress induced in rats led to hypothalamic suppression of reproductive function (2009).

Weight

Obesity can reduce fertility in males through hormonal and physical factors (Cabler et al., 2010). Hormonal factors: Obese men have high levels of white adipose tissue which exhibit high levels of aromatase activity. Aromatase is an enzyme that helps convert androgens, such as testosterone into estrogen. Therefore, the reduction of testosterone levels via aromatase activity can contribute to male infertility. Physical factors: Obese men are found to have increased scrotal fat, which may lead to increased testicular temperature.

Andrology Australia. 2018, June 1. Male infertility. Retrieved Novem 13, 2018, from https://andrologyaustralia.org/your-health/male-infertility/

Basu, S. C. (2014). Psychological Stress and Male Infertility. In Male Infertility (pp. 141-159). Springer, New York, NY.

Cabler, S., Agarwal, A., Flint, M., & Du Plessis, S. S. (2010). Obesity: modern man's fertility nemesis. Asian journal of andrology, 12(4), 480.

Gude, D. (2012). Alcohol and fertility. Journal of human reproductive sciences, 5(2), 226.

Kirby, E. D., Geraghty, A. C., Ubuka, T., Bentley, G. E., & Kaufer, D. (2009). Stress increases putative gonadotropin inhibitory hormone and decreases luteinizing hormone in male rats. Proceedings of the National Academy of Sciences.

Kovac, J. R., Khanna, A., & Lipshultz, L. I. (2015). The effects of cigarette smoking on male fertility. Postgraduate medicine, 127(3), 338-341.

Mayo Clinic Staff. (n.d.). Male infertility - Symptoms and causes. Retrieved November 13, 2018, from https://www.mayoclinic.org/diseases-conditions/male-infertility/symptoms-causes/syc-20374773?p=1

Xu, H., Tanphaichitr, N., Forkert, P. G., Anupriwan, A., Weerachatyanukul, W., Vincent, R., … & Wade, M. G. (2004). Exposure to trichloroethylene and its metabolites causes impairment of sperm fertilizing ability in mice. Toxicological sciences, 82(2), 590-597.