Why doesn't the sperm die if there is citric acid and acid phosphatases in the semen?
Citric acid is a weak acid so in the context of a buffered physiological medium (semen pH 7.7) it will not cause any significant acidification. Acid phosphatases are enzymes with a pH optimum below 7 (as distinct from alkaline pho sphatases). Their presence has no implications for the pH of semen, although it is interesting to speculate why an alkaline fluid would contain an acid phosphatase.