- 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.