Semen (also known as “ejaculate”) is the thick, usually white fluid that emerges from the penis during ejaculation. Semen contains sperm, as well as substances that protect and nourish sperm on their journey. Semen is responsible for carrying sperm outside the male body and into the female reproductive system, in order to fertilize the egg and create an embryo.

What is semen?

Semen is the fluid ejaculated from a penis, typically during an orgasm. It contains sperm, and when released inside the female reproductive tract, it transports sperm to fertilize an egg. Semen is also called ejaculate or cum.

Ingredients in semen

Semen is made up of a combination of sperm, water, mucus, and other fluids. Healthy semen contains at least 15 million spermatozoa per mL. Additional fluids in semen are secreted by the prostate, seminal vesicles, testis, epididymis, and bulbourethral glands.

Secretions from the seminal vesicles make up the majority of the semen volume, containing fructose (an energy source for sperm) and vitamin C (an antioxidant to protect sperm). Fluids from the prostate contain zinc (an essential mineral), cholesterol, and fatty acids. These nutrients also help protect and power sperm. A small amount of mucus is added by the bulbourethral glands.

Semen and male fertility

Semen quality is an important indicator of male fertility. Having a low concentration of sperm in your semen can make it more difficult to achieve a pregnancy. Male infertility accounts for approximately one-third of infertility issues in couples and affects around 7% of men. Examining the semen is often an essential step to determine the source of infertility.

Testing semen quality

Semen quality can be measured through a semen analysis. The test looks at the quality and quantity of sperm. Specifically, it measures:

Low sperm count, low sperm motility, and abnormal sperm morphology may contribute to infertility. Low sperm count is associated with as many as 90% of male fertility issues.
Studies suggest that a semen analysis is able to detect 9 out of 10 cases of male-factor infertility. Note, however, that even if a semen analysis finds abnormalities, your sperm may still be capable of fertilizing an egg and conceiving a child.

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