Spermatozoon (single), Spermatozoa (plural):
Often abbreviated as Sperm or sperms.

Sperm is produced in man over his life-span although the quantity and quality can vary considerably. The World Health Organization (WHO) suggests that 20 million motile sperm per ml of semen is necessary for conception via intercourse - much variation can occur in a normal man who is not subject to any medication.

Note that there is considerable variation in the sperm count taken bi-weekly. At times the count is as high as 180 million sperm/ml, at other times it drops below the 20 million sperm/ml level into the red zone (below the WHO figure for acceptability) and sometimes to zero. Many factors influence sperm counts e.g. temperature, alcohol, smoking, infections.

In male factor infertility - where the cause can be identified as being on the male side - reasons for failure in conception may be due to low numbers (Oligozoospermia - often referred to as oligospermia), poor motility (asthenozoopermia or asthenospermia), abnormal forms (Teratozoospermia -or teratospermia) or a combination of them all OATS - Oligo-astheno-teratospermia. Sperm dysfunction may also occur - quality, quantity and morphology seem normal yet fertilisation fails to occur - it is the most common form of infertility.