By Dr Ananya Mandal, MD
Semen is a bodily fluid that is secreted by the gonads of male animals. It contains spermatozoa and fructose and other enzymes that help the sperm to survive to facilitate successful fertilization. During the process of ejaculation, the semen is ejaculated from the seminal vesicle in the pelvis, which is where it is produced.
Composition of semen
Semen passes through the ejaculatory ducts and mixes with fluids from the seminal vesicles, the prostrate, and the bulbourethral glands.
The seminal vesicles produce a viscous, fructose-rich fluid. This forms around 65-70% of the semen base.
The white color of the semen is due to secretion from the prostate glands containing enzymes, citric acid, lipids, and acid phosphatase. This forms around 25-30% of the semen base.
At each ejaculation around 200-500 million spermatozoa are released by the testes. This forms about 2-5% of the semen composition.
Apart from these the bulbourethral glands produce a clear secretion. This helps in mobility of the sperm cells in the vagina and cervix. In addition, this clear secretion reduces the thickness of the channel that the sperm cells swim through and adds a cohesive, jelly-like consistency to the semen. The glands’ secretion contribute less than 1% to the overall semen composition.
Thus semen contains:
blood group antigens
Amount of semen per ejaculate
The volume of semen released per ejaculate varies. Approximately an average around 3.4 milliliters is ejaculated at one time. It can be as high as 4.99 milliliters or as low as 2.3 milliliters.
If there is a prolonged gap between ejaculations, the number of sperm in the semen increases but there is no overall increase in the semen.
Possible beneficial effects of consumption of semen
There are mixed reports regarding the effects of swallowing semen. Some studies suggest that absorption of semen via the vaginal mucus membrane lining its inner walls has positive effects like reducing depression and also reduces the risk of breast cancer.
Some women are infertile or lose pregnancies due to miscarriages due to their inherent presence of antibodies that destroy the proteins or antigens present in her sexual partners semen. Having oral sex and swallowing the semen of the partner may help make the pregnancy safer and more successful as the woman is swallowing her partner's antigens.
Possible disadvantages of consumption of semen
Semen can contain several viruses that may be transmitted via bodily fluids from an infected man. The most common example of such sexually transmitted infections (STI) are HIV (Human Immunodeficiency virus) and Hepatitis B and C viruses, herpes, Chlamydia etc.
There are some studies that suggest that vaginal absorption of semen can accelerate the development of an already existing cervical cancer. This occurs due to the prostaglandin present in semen.
Cultural practices and beliefs
Some cultures believe that semen has special properties of masculinity. The idea of semen being associated with masculinity was prevalent in ancient Greece when Aristotle considered semen to be very important.
He said that there existed a connection between blood and semen. He believed that semen was produced from blood using body heat. He believed that too early initiation of sexual activity may mean loss of semen and a loss of valuable and much-needed nourishment.
In Papua New Guinea some communities believe that semen provides sexual maturation to the younger men of the tribe. The tribes believe that the semen of older men can bestow manliness and wisdom to the younger men and for this the men need to fellate their elders to receive their authority and powers.
In ancient eastern cultures gemstones are believed to be drops of divine semen. Chinese believe jade is the dried semen of the celestial dragon.
Reviewed by April Cashin-Garbutt, BA Hons (Cantab)
Last Updated: Jan 3, 2014