Fertility is the physical capacity to give life. Human Fertility based on factors of nutrition, sexual behaviour, culture, instinct, endocrinology, timing, the economy, lifestyle and emotions. Animal fertility is no less complex and may display mechanisms staggering. Fertility is also applied to agricultural land and plants, where it requires a great ability to produce good harvests healthy fruit, seeds or vegetables.The fertility rate is a measure demographic in the number of children per woman. Although it was until recently regarded as a fairly good indicator of population growth, it is no longer the case in much of Asia.Both men and women have hormonal cycles, which also determine well when a woman can get pregnant and when a man is most fertile. The female cycle is approximately twenty-eight days.

Age also plays a role, especially for women.Women are fertile about seven days in each menstrual cycle. Ovulation occurs around the fourteenth day of their menstrual cycle, it is obviously the most fertile time for women. Women 's fertility peaks around age 23-24, and often dangerous after 30. With an increase of women to postpone pregnancy, it can create a problem of infertility. Approximately 9 percent of pregnancies for women recognized aged 20 to 24 ended in miscarriage. Mucus cervix is one of the most important indicators of fertility, because it changes throughout the menstrual cycle to be dry, thick or pasty (sterile) to be wet and slippery (fertile). The risk increased to about 20 percent at age 35 to 39 and more than 50 percent in 42 years. "

Male fertility does not diminish as it does with the women, there were examples of men to be fertile to 94 years. At most, age "could possibly result in a moderate decline" in fertility in males. Spermatozoa slightly decreases with age, with men aged 50-80 years of semen at an average rate of 75% compared to men aged 20-50 years. Infertility is just as likely to be related to male factors as female factors. Approximately 85% to 90% of infertility can be treated with conventional therapies, such as drugs or surgery. Fertility drugs are often the first treatment for women who aren 't ovulation. Drugs are also used in other more complicated assisted reproduction treatments such as in vitro fertilization and intrauterine insemination.