What does fertile mean? Many couples trying to start a family may wonder when they begin hearing physicians throw around phrases like "peak fertility" or "fertility treatments". In the most basic sense, fertile just means capable of bearing offspring, but in a human context, it's much core complex than that.

Female Fertility

Women generally become fertile between the ages of 10 and 16 when they go through puberty and begin menstruating. Cycles can be irregular for the first couple of years, however, and girls often don't ovulate every month. Women hit peak fertility at approximately 27 years of age, and fertility begins to decline after age 30. After 35, the chances of miscarriage also increase. Even during peak fertility, a woman is actually only fertile for three to four days out of every cycle. This is because after a mature unfertilized egg is released by the ovaries during ovulation, the egg can only survive unfertilized up to 24 hours. If the egg is fertilized during this time, it will continue down the fallopian tubes and implant in the lining of the uterus. If it isn't, the uterine lining will absorb the unfertilized egg and it will be flushed out with the woman's next period. Although the egg can only survive unfertilized for a day, when it comes to sexual intercourse, women have as many four fertile days during their cycle, because sperm can survive for up to three days in the female body, waiting for the ovaries to release the mature egg.

Male Fertility

While on the face of things male fertility seems simple compared to female fertility, it can still get complicated. Men become fertile during puberty when their testes begin producing sperm. Male fertility lasts longer than female fertility, but it does begin to decline significantly with age. Male infertility is a factor in half of infertility cases, and the primary cause in a third of them. The main causes of male infertility are irregular sperm production or function, impotence, lifestyle factors, and exposure to environmental toxins.

Their Fertility

A couple generally isn't diagnosed with fertility problems unless they've been having regular unprotected sex for a year without a resulting pregnancy. However, doctors recommend seeing a fertility specialist for an initial consult if you've been having unprotected sex for six months without results, or if the woman is already over 35.