Pink, red, or brown sperm may mean that a man has blood in his semen, and this can be the sign of an infection or injury. Semen color can change from day to day, and a sudden change or a change accompanied by discomfort or a foul odor should be checked by a physician.hen one refers to sperm color, he is usually referring to the color of semen. Usually, semen is white or grayish in color, due to the large amount of proteins present in the secretions. Yellow may also be a normal sperm color for some men.