Sometimes producing an unusual colored semen is a once-only occurrence. Other times, a man may notice a more consistent change in the color of his semen.

Semen as a substance is a combination of secretions from the male reproductive glands as well as sperm. Changes and disruption to these areas are what cause color changes.

The following are responsible for semen production:

• Epididymis and testicles: The testicles are the organs responsible for producing sperm. The epididymis is the tube that transports sperm from the testicles to the vas deferens.
• Seminal vesicles: These produce a significant portion of the semen’s volume. These glands produce secretions that are high in a sugar called fructose, which provides nutrients to the sperm.
• Prostate gland: This gland produces a chemical called prostate-specific antigen (PSA) that causes a reaction in the gel-like semen, allowing the sperm to swim away and reach an available egg more easily.
• Bulbourethral and urethral glands: These glands are responsible for producing secretions that make it easier for semen to travel along the reproductive tract.

Each of these parts of the male reproductive organs and glands plays a role in ejaculation.

Causes of yellow semen

Although semen is usually a whitish-gray color, some men may have sperm that is yellow.

However, if yellow semen represents a significant color change for a man, this could be cause for concern.

Some potential causes associated with yellow semen include:

• Urine in the semen: Semen travels through the urethra, which is the same tube that urine travels through. It is possible that some yellow-tinted urine can mix with semen, which would give semen a yellow tint or cast.
• Jaundice: This results when the liver has difficulty breaking down bilirubin, a by-product of red blood cell destruction. Jaundice most commonly causes yellowing of the eyes but can cause the skin and the semen to appear yellow too.
• Abnormally high white blood cells: Inflammation can produce excess white blood cells. These can be released via the semen, a condition known as pyospermia or leukocytospermia. Additional white blood cells can cause semen to appear yellow. These can be the result of an infection.
• STIs: A sexually transmitted infection, such as chlamydia, herpes, or gonorrhea may cause yellow semen. In this instance, a man’s semen may also have an unpleasant smell.
• Dietary changes: Eating foods that contain dyes can cause yellow semen. The smell of ejaculate may also change if a man eats strong-smelling foods, such as garlic, onions, asparagus, or broccoli.
• Infrequent ejaculation: If a man has not ejaculated in some time; the semen is more likely to have mixed with urine.