Why is my semen yellow?
Blood in Semen (Hematospermia)
Other times, a man may notice a more consistent change in the color of his semen. Although this occurrence is not always a cause for colored, there are some instances when semen color change can be cause indicator of an underlying cause condition.
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.