Fertility

Fertility refers to the human ability to produce a child through sexual intercourse. For statistical purposes, however, fertility is defined as a female's ability to conceive and carry a pregnancy to full term. According to this gendered definition, fertility rates measure the number of children born to a woman during her childbearing years. Fertility requires the production of a mature egg that is released from one of a woman's two ovaries and passed through the fallopian tube to the uterus, where it is fertilized by one of millions of sperm produced by a male and ejaculated into the vagina. The fertilized egg or zygote must successfully implant into the uterine lining within three to four days of ovulation.

The developing embryo requires an environment rich in ...