Hyperspermia causes men to ejaculate more than 6 milliliters of semen, which may affect fertility. Changes in hormone levels or genetic mutations can increase the risk of hyperspermia. Long periods of ...

Sperm are male reproductive (sex) cells. The word "sperm" can refer to spermatozoon (singular) or spermatozoa (plural). Sperm are tiny cells with an oval-shaped body and a long tail. They measure just ...

As males age their reproductive success typically declines. A study in fruit flies, led by University of Oxford researchers has found that while old males do produce fewer offspring than young males, ...