• Varicocele, are dilated veins in the scrotum, (just as an individual may have varicose veins in their legs.) These veins are dilated because the blood does not drain properly from them. These dilated veins allow extra blood to pool in the scrotum, which has a negative effect on the sperm production. This condition is the most common reversible cause·
• Blockages or obstructions of male reproductive tract, creating oligospermia (low sperm count) or azoospermia (zero sperm count) ·
• Congenital absence of the vas deferens, rendering sperm incapable of travelling to their intended destination; sometimes related to being a healthy carrier of cystic fibrosis disease ·
• Non-obstructive azoospermia, in which blockage is not to blame; may be a result of the male missing part of the Y chromosome ·
• Klinefelter's syndrome or other genetic conditions·
• Hydrocele - the presence of excessive fluid. There can occasionally be anatomical defects in the development of the penis. Consequently, during intercourse and ejaculation the sperm cannot be deposited within the vagina very easily. Retrograde ejaculation is a rare condition when some men ejaculate backwards into the bladder. This could be the result of earlier surgery to the urethra (the outflow tube from the bladder). ·
• Prostate problems - A rectal examination can help determine whether there are any problems with the prostate gland.
• Cancer treatment - some drugs can cause problems with sperm production

Possible causes of a low sperm count.·

• Infected semen can be a cause of infertility
• Heat can reduce sperm production
• Very frequent intercourse - If you want to be at your most fertile you have to wait at least 3 days between each ejaculation!
• Smoking has been shown to reduce both the sperm count and the sperm motility
• Excessive alcohol intake
• Stress and overwork
• Drugs
• Cancer treatments
• Sexually transmitted diseases (STD's)