Fertility is the state of being fertile and capable of producing offspring. Initially the term fertility was associated only with females but with better understanding of the reproductive mechanisms and the importance of the role that men play in reproduction, it is now equally associated with men as well. Many oriental philosophies argue that reproduction is the primary motive behind existence.

Humans have a natural tendency to seek information and knowledge about whatever concerns them. And fertility is an area most of us are eager to understand since conception and childbirth are instrumental in bringing about a metamorphosis of great magnitude in women. Men also are fairly concerned about their partner’s ability to conceive or their inability to do so. Understanding the basics of human fertility goes a long way in allaying any concerns that may arise in the minds of couples who want to start a family.

All humans have hormonal cycles that determine when a woman can conceive and when a man is most fertile. The female fertility cycle is usually 28 days but this may vary depending on the individual and may be more or less by a few days. The male cycle, however, is totally variable.

Female fertility
Among women, fertility is the ability to conceive and give birth to a child. The reproductive years of a woman begin when her she attains puberty with the first menstrual cycle. This usually happens around the age of thirteen and lasts till about the age of forty five. This range is only indicative and women are known to have conceived and delivered till menopause, which is the cessation of her periods.

At the time of birth, a baby girl already has four hundred thousand eggs which are immature and stored in her ovaries in small sacs called follicles. The follicles are filled with fluid that protects the immature cells. At puberty the eggs start to mature one at a time. During each menstrual cycle the ovary releases one egg (in rare cases it releases more than one) in the process called ovulation. The delicate balance of hormones released by the ovaries and the hypothalamus and pituitary in the brain dictates how the egg will develop and when it shall be released.

Ovulation sometimes happens with a small but sharp pain and the egg is released. This egg travels up the fallopian tubes and may get fertilized by a male sperm if available. Successful fertilization results in conception. If the egg is not fertilized, it bursts and breaks down within 24 hours and the proteins that it is made up off get reabsorbed by the body. The lining of the uterus that has been prepared in anticipation of the fertilized egg breaks down and is removed from the body during the menstrual period.

For women the chances of pregnancy are directly related to age. Women are most fertile in their early twenties and their fertility often starts ebbing after they reach 30. The use of fertility drugs or in-vitro fertilization can change this and it has been known that the use of these methods can result in pregnancies even at the age of 67.

Male fertility
Fertility in men is mostly about ability to make a woman pregnant. Men need to produce, and store sperm in their bodies. This stored sperm needs to then be transported outside the body into the reproductive tract of a woman.

Sperms develop in seminiferous tubules in testicles that are housed in a sac called the scrotum that is located just behind the penis. Men can produce and ejaculate sperm anytime during the month. The stock of sperms is refreshed every 72 days. This ability to produce fresh sperm lasts a lifetime till the organs are functioning properly.

However, their sexual urge and desire can dip occasionally. Scientists refer to this swing in the sexual urge as the internal cycle of men. Some studies suggest that the internal cycle of men may be related to the partner’s monthly cycle.