Fresh ejaculated semen is usually off-white or milky white, not transparent. Fresh semen is in the form of thick jelly and starts to liquefy after 5 minutes, and it usually takes about 15-20 minutes for semen to completely liquefy, and after complete liquefaction, semen will usually be transparent. The normal volume of semen ejaculated at one time is about 2-5 ml, and the number of sperms contained in semen is about 300-500 million sperms. Semen consists mainly of spermatozoa and seminal plasma, which is a mixture of seminal vesicle fluid, epididymal fluid and prostate fluid. Usually the spermatozoa that are ejected from the body survive for about 24 hours or so. Common disorders of semen, mainly reduced sperm motility and abnormal sperm morphology.