What is fertility?

Fertility means:

  • being able to get pregnant
  • or being able to make someone pregnant.

The parts of your body that help you do this are called your reproductive system.

A man makes sperm in his testicles. A woman has eggs stored in her ovaries.

To start a pregnancy, a man’s sperm needs to fertilise a woman’s egg. This fertilised egg may grow into a baby.

This may happen naturally when a man and a woman have sex. Some people have difficulty starting a pregnancy naturally and may need treatment to help them. This treatment is called fertility treatment or assisted conception.

Fertility in men

In men, the reproductive system includes the testicles (balls), the penis and the prostate gland. A small gland (called the pituitary gland) at the base of your brain releases hormones which are also important. Hormones are chemicals in the body that help control how the body works. The hormones from the pituitary gland control how your reproductive system works.

Male reproductive system
Male reproductive system

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Fertility in men depends on:

  • having healthy sperm
  • being able to get an erection (hard on) and to ejaculate (come)
  • having the right hormone levels.

The testicles begin to make and store sperm from puberty onwards. Puberty is when your body begins to change from a child into an adult. This happens around the age of 12 for boys.

Hormones from the pituitary gland and the testicles control sperm production. The testicles make the hormone testosterone. Testosterone helps you want to have sex and to get an erection.

Normally, you need to have sex to fertilise a woman’s egg with your sperm. This means getting an erection and ejaculating in a woman’s vagina. The fluid released from the penis during sex is called semen. Semen contains millions of tiny sperm from the testicles and fluid from the prostate gland. One of the sperm may fertilise an egg, which can then grow into a baby.

Fertility in women

In women, the reproductive system includes the ovaries, fallopian tubes, womb (uterus), cervix and vagina. A small gland (called the pituitary gland) at the base of your brain releases hormones which are also important. Hormones are chemicals in the body that help control how the body works. The hormones from the pituitary gland control how your reproductive system works.

Female reproductive system
Female reproductive system

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You are born with lots of eggs that are stored in your ovaries. No more eggs are made after you are born. Normally, once a month, one of your ovaries releases an egg. The hormones from the pituitary gland help control this process. This happens from puberty to the menopause.

For you to get pregnant, one of your eggs needs to be fertilised by a sperm. This may happen if you have sex. After being released from the ovary, the egg moves along the fallopian tube. If it meets a sperm and is fertilised, the egg develops into a collection of cells called an embryo. The embryo moves to the womb where it settles into the womb lining. The embryo stays in the womb and grows into a baby.

Hormones help to make the lining of the womb ready for the embryo. If the egg is not fertilised, the womb lining comes out through the vagina as your monthly period.

Puberty and menopause in women

Puberty is when your body begins to change from a child into an adult. This happens around the age of 11 for girls.

As women get older, the number and quality of eggs in the ovaries decreases. When there are very few eggs left, you go through the menopause. For most women, this happens naturally between their mid-40s and mid-50s. Hormone levels in the body change and the ovaries stop releasing eggs each month. Your periods gradually stop and you can’t get pregnant anymore.