fertility

Organism's ability to reproduce, as distinct from the rate at which it reproduces (fecundity). Individuals that can reproduce are fertile. Individuals that cannot reproduce are infertile. Individuals become infertile (unable to reproduce) when they cannot generate gametes (eggs or sperm) or when their gametes cannot yield a viable embryo after fertilization. Common causes of infertility are: low sperm numbers in the male; blocked oviducts; infrequent ovulation (release of gamete) in the female; consequence of infections in the female reproductive tract; and genetic makeup.