Investigation of Reproduction and Development in Animals Cycles, Conception and Contraception Fertility is the condition of being fertile. The aim of contraception is to inhibit fertility in individuals, hence, slowing population growth. The system by which all female contraception must operate: the menstrual cycle. What is the menstrual cycle? and what hormones are involved in controlling it? After puberty, the female produces an egg each month. Other changes take place on a cyclic basis including the uterus lining and hormone levels. These changes are called the men