Fertility in Biology Explained for Students

Fertility is the ability of an individual or couple to produce a child through normal sexual activity. Around 90% of healthy, fertile women can reproduce in one year if they have intercourse regularly without contraception.  Fertility is most commonly considered when there is the inability to reproduce naturally, and it is also referred to as infertility. 

Natural fertility requires the production of enough healthy sperm by the male and living egg by female, successful transit of the sperm through open ducts from the male testis to the fallopian tube, penetration of a healthy woman, and implantation of the fertilized egg in the lining of a uterus. An issue with any of these steps can cause infertility. Human fertility depends on a number of factors like nutrition, culture, endocrinology, instinct, timings, consanguinity, and emotions.

Fertility Definition

The term 'fertility' is defined as the state or quality of being fertile.

What is the Meaning of Fertility?

Fertility is the natural ability to give life. In humans and animals, fertility means that parents can reproduce. More precisely, fertility means the ability of a parent to produce viable offspring. The term “viable” implies  “able to live and give birth”.

In agriculture, fertility means the ability of soil to support the growth of the plants because it contains the right proportion of minerals and nutrients. 

What is Meant By Fertility in Humans?

Fertility means the quality of being productive. Physiological, the term fertility refers to the ability to conceive a baby. Before people had a better understanding of the human population, the term fertility was applied to a woman but now the term fertility may apply to either sex. 

Virility refers to the wide range of masculine characteristics observed positively and suggests robust sexual activity and the ability to impregnate women. The term virility is commonly associated with healthy, strength, perseverance, and constitution. Hence, virility is to men and fertility is to women.

Biologically, women can become fertile at puberty ( usually between the ages 10-13) when the ovaries begin to function. Each month, a woman ovulates (releases an egg). Ovulation generally takes place around day 14 of a 28 days menstruation cycle. The woman is most fertile during this time. Fertilization may occur in the fallopian tubes if the sperm is present with the resulting embryo implanting in the uterus.

Women continue to release one egg each month throughout their reproductive years, though women’s fertility begins to diminish after the age of 30.  Infertility occurs in only 5% of women in their thirties. However, by the time, they reach 30, they can expect 25% of their infertility which is defined as the inability to conceive a baby after one year of unprotected sex ( six months if the woman is 30 or older). The chances of delivering a healthy baby are even less due to miscarriage or other health conditions. 

The arrival of menopause near the age of 50 marks the stoppage of the women’s menstruation cycle and her ability to reproduce. However, men remain sexually fertile throughout most of their adulthood. After the arrival of puberty, when the pesticides begin to function, males can produce a continuous supply of sperms, capable of impregnating women (though males fertility does diminish with age).

Fertility Problem Sign

It is common for a couple to observe fertility issues after they have tried to get pregnant unsuccessfully for a year. Most of the causes of infertility are silent and they don't have obvious symptoms. However, the following signs may indicate a fertility issue and may give you signal to appoint a doctor. 

• Your age is 35 or more, and you have been trying to conceive for 6 months.

• Your age is less than 35 and you have had unprotected sexual intercourse for one year without getting pregnant.

• You may have faced two or more successive pregnancy losses.

• You may have any risk factor for infertility.

The Most Common Symptoms of Fertility Issues are as Follows:

• Menstruation cycles are irregular.

• Pelvic pain or pain during sexual intercourse.

• Unusual heavy period or abnormal menstruation bleeding.

• Bad menstruation cramps and unusual light or heavy periods.

• Sexual Dysfunction (the term means the problem that you may have which prevents you from wanting or enjoying sexual activity). 

Did You Know?

• Women are born with about 1 million to 2 million eggs but able to release only 300-400 during ovulation during their lifetime. Generally, women release only one egg each month.

• Generally, the best chance for women to get pregnant is when sexual intercourse occurs 1-2 days before ovulation.

• As per the UN Population Division, a total fertility rate of 2.1 children per woman is known as replacement-level fertility.

• Replacement fertility is defined as the total fertility rate (TFR) at which women give birth to enough young ones to preserve population growth.

• Nigeria has the highest total fertility rate in the world with 6.91 children born per woman( estimates in the year 2001).