Q. What's in semen? I ask because it tastes salty and the doctor says I have to cut down on my salt intake. Also what is the pH level? Do you know? I have heard it messes your insides up too if you swallow. What are the effects and are they harmful?

Dr Dawn Harper replies:

Semen is made up of sperm and secretions from the seminal vesicles, prostate and other glands in the genital tract. It tastes salty because it does contain some salt like all body fluids – tears taste salty too, but the salt content is not sufficient to cause you any problems, and swallowing will not “mess up your insides”.

Normal semen should be clear or white in colour, a yellow tinge may suggest infection and pink or brown, could mean there is blood. This may simply be due to overzealous masturbation but should be checked out by a doctor. When first produced it tends to be thick and slightly sticky but becomes more watery over time. Normal volumes range from 2 – 6 millilitres (about ½ to 1 teaspoon) and it’s slightly alkaline, the pH being 7.2 – 7.8.