Progesterone serves many functions in pregnancy. It prepares the endometrial lining for implantation of the embryo, it increases the contractility of the uterus, it inhibits lactation during pregnancy, and it is thought to reduce maternal immune response to the developing fetus. Breast enlargement and maturation in preparation for lactation is facilitated by estrogen, rather than progesterone.

Testis-determining factor, also known as sex-determining region Y (SRY) protein, is a sex-determining gene found exclusively on the Y-chromosome in humans. It's transcription triggers the development of male sexual characteristics in the developing fetus.

The Sertoli cells of the testes are responsible for the secretion of many substances, including anti-Müllerian hormone, androgen binding protein, glial cell line-derived neurotrophic factor, and estradiol.

The process by which post-ejaculatory sperm is rendered fully mature and capable of fertilization of an ovum is called capacitation. This is where enzymes within the uterus are able to partially degrade the acrosome, the cap surrounding the head of the spermatazoa, allowing it to bind with and eventually penetrate the zona pellucida of the egg.

The stability of sperm cell chromatin is dependent on zinc. Zinc deficiency can cause sperm to be fragile, which in turn lowers sperm count and decreases male fertility.

Male ejaculate can contain any where from 40 million to 1 billion sperm, though the average ejaculate contains between 100 and 400 million. 

The primary energy source of spermatozoa is fructose, produced by the seminal vesicle along with multiple amino acids, vitamin C, enzimes, and flavin. 

Fully formed spermatozoa from the seminal vesicles are transported to the epididymis, where they are stored for 2-3 months. During ejaculation, stored sperm are moved from the lower epididymis via peristaltic action of the muscle layers of the vas deferens, mixed with various fluids to form semen.  

Seminal fluid is formed by several glands: the prostate contributes proteolytic enzymes, citric acid, acid phosphatase, zinc, fibrinolysin, and prostate specific antigen. The seminal vesicles contribute various flavins, fructose, and amino acids. The bulbourethral glands secrete a mucus that allows the semen to travel rapidly through the urethra, potentially aiding its route toward the cervix.  

The prostate, a fleshy endocrine gland inferior to the outlet of the male bladder, secretes a slightly alkaline milky fluid that makes up one third of the volume of semen. This alkalinity helps neutralize the acid environment of the vagina, increasing the likelihood of conception. Lubrication of the urethra is provided by the bulbourethral gland, while fructose is produced within the seminal vesicles. The prostate does not take part in sperm production.