Fertility is the natural capability of giving life. As a measure, "Fertility Rate" is the number of chilren born per couple, person or population. This is different from fecundity, which is defined as the potential for reproduction (influenced by gamete production, fertilisation and carrying a pregnancy to term). In the English language, the term was originally applied only to females, but increasingly is applied to males as well, as common understanding of reproductive mechanisms increases and the importance of the male role is better known. Infertility is a deficient fertility.