Semen is a bodily fluid secreted by the gonads of male animals.
In humans, semen contains spermatozoa and fructose as well as other enzymes which promote the survival of the spermatozoa. During a process known as ejaculation, the semen is ejaculated from the seminal vesicle in the pelvis, which is where it is produced.
Physical Composition
Because the semen passes through the ejaculatory ducts and mixes with fluids from the seminal vesicles, the prostrate, and the bulbourethral glands, semen is composed of many different fluids.
- The seminal vesicles produce a viscous, fructose-rich fluid. This fluid makes up approximately 65-70% of the semen base.
- The whitish secretion from the prostate contains enzymes, citric acid, lipids, and acid phosphatase. This secretion composes around 25-30% of the semen base.
- The testes eject approximately 200-500 million spermatozoa during ejaculation. They compose about 2-5% of the semen composition.
- The bulbourethral glands produce a clear secretion that increases the mobility of the sperm cells in the vagina and cervix. It lessens the viscosity of the channel that the sperm cells swim through and also adds a cohesive, jelly-like texture to the semen. The glands contribute approximately less than 1% to the overall semen composition.
The volume of semen per ejaculation varies. A comparison of thirty studies suggests that the average amount of semen ejaculated was around 3.4 milliliters, although some studies found amounts as high as 4.99 milliliters or as low as 2.3 milliliters. It is believed that a prolonged gap between ejaculations increases the number of sperm in the semen but not an increase of the overall amount of semen.
Health Effects
Studies have revealed mixed conclusions about the impact of semen on the human body.
Some of the alleged positive impacts suggest that vaginal absorption of semen acts as an antidepressant and reduces the risk of breast cancer, while oral sex may help make a woman’s pregnancy safer and more successful because she is swallowing her partner’s antigens. However, one study suggested that vaginal absorption of semen could accelerate the development of an already existing cervical cancer, due to the prostaglandin elements in seminal plasma. So results are inconclusive, and more studies are needed to definitively determine whether ingesting semen has beneficial or negative impacts on the human body.
However, it is worth noting that semen can be the vehicle for many sexually transmitted diseases, such as HIV/AIDS, herpes, or chlamydia. Although the proteins present in semen are potent against bacteria, fungi, and some viruses, these proteins are not active against Neisseria gonorrhoeae, which is the common cause of sexually transmitted diseases.
Cultural Practices and Beliefs
Some cultures view semen as imbued with special properties of masculinity. For instance, many tribes in Papua New Guinea (such as the Sambia and the Etoro) believe that semen provides sexual maturation to the younger men of the tribe. Because they view the older men’s sperm as bestowed with the manliness and wisdom of the tribal elders, the younger men must fellate their elders to receive their authority and powers.
In ancient Greece, Aristotle considered semen to be very important and believed that there was a connection between blood and semen. He thought that the males concocted blood into semen using body heat. He also warned against engaging in sexual activities at too early of an age, fearing that the loss of semen meant a loss of valuable and much-needed nourishment.
Many ancient Eastern cultures believed that gemstones were drops of divine semen, which had coagulated after fertilizing the earth. In ancient China, for instance, some believed that jade was the dried semen of the celestial dragon.
Additionally, the orchid’s twin bulbs were considered physically similar to a man’s testicles. This popular conception probably gave rise to the ancient Roman myth that the flower originated from the spilled semen of copulating satyrs.
