What can affect a man’s fertility
A semen analysis may reveal various reasons why sperm have difficulty in fertilizing an egg. The sperm count may be low (less than 20 million sperm per ml); the motility of the sperm (how they move)may be poor; and there may be a high percentage of abnormally formed sperm. Some men experience a failure to ejaculate at orgasm. There
may also be damage to the tubes that connect the testicles to the seminal vesicles where sperm are produced, and this may have been present from birth or caused by a later infection