Spermatogenesis is the process of sperm production that occurs in the seminiferous tubules of the testes and involves various steps and precise spatial organization and timing. Spermatogenesis is a complex process that takes approximately 64 days. The average male produces about 30 million sperm a day.

Spermatozoa are a perfect example of streamlined evolutionary design. They are lightweight, highly motile, and effectively deliver DNA to the female fallopian tube where the egg awaits fertilization. A mature sperm has a pear-shaped head with a nucleus, acrosome, and flagellar basal body. The nucleus makes up most of the head and contains genetically inactive chromosomes. The tip of the nucleus is covered by a protein-filled cap called the acrosome, which contains enzymes that are necessary for sperm to penetrate the egg. The midpiece of the tail, closest to the head, is made up of mitochondria which provide energy for the flagellum to move and propel the sperm.

Sperm consists of the following nutrients: acid phosphatase, citric acid, inositol, calcium, copper, zinc, magnesium, selenium, fructose, semenogelin, vitamin E, vitamin C, prostaglandins, carnitine, glycerophosphato-choline, neutral alpha-glucosidase, protein, carotenoids, sodium, potassium, glucose, urea, lactic acid, and cholesterol.

The sperm cell membrane comprises fatty acids that ensure proper function, allowing for successful fertilization events, including capacitation, acrosome reaction, and sperm-oocyte fusion. As spermatozoa mature, they accumulate increasing amounts of polyunsaturated fatty acids (PUFAs), specifically, docosahexaenoic acid (DHA), in the cell membrane. Within the cell membrane PUFAs act as structural components that contribute to fluidity and permeability.

Semen contains many essential nutrients that allow for the proper maturation and function of spermatozoa as a result of spermatogenesis. Semen is composed of several secretions from various glands that contain nutrients, buffers that protect sperm from the acidic environment of the vaginal, chemicals that increase sperm motility, and prostaglandins. The seminal vesicles contribute yellowish secretions that make up 60% of the semen, and the prostate contributes a thin milky secretion that makes up 30% of the semen. Together, these fluid secretions and sperm cells make up semen.

Oxidative stress occurs when there is an imbalance in free radicals or reactive oxygen species (ROS) production and the antioxidant defense mechanisms that neutralize the harmful effects of these toxic products. As spermatogonia transform through the complex spermatogenesis processes into mature spermatozoa, they are vulnerable to oxidative stress. Several events of spermatogenesis, including the loss of cytoplasm, mitochondrial generation of ROS, and accumulation of highly oxidizable PUFA in the cell membrane, make sperm highly susceptible to oxidative damage.

Obesity and declining sperm count have become health concerns for male reproductive function and sperm quality. Males with a BMI greater than 30 are more likely to have hypogonadism, impaired spermatogenesis, and alterations in reproductive hormones, including decreased testosterone and excess estrogen. Additionally, chronic oxidative stress caused by obesity can cause systemic inflammation, affecting testicular tissue semen and disrupting sperm function.