A reader asks: I was alarmed recently to see that my sperm was dark brown. Is this normal for a man of 61?

Simon says: Semen should be creamy white and a change to brown may suggest there is blood in it. One common reason could be trauma from a sports injury or even a bicycle saddle. Infections can also cause bleeding , as can inflammation or enlargement of the prostate gland. In men under 40, the most likely cause is inflammation, but over the age of 40 there is a very small chance of a malignant cause so it's advisable to get it investigated.

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