Human reproductive system

The human reproductive system includes the male and female parts of the body that help humans have babies. The male part makes and puts out tiny cells called sperm. The female part makes egg cells and also keeps and cares for a growing baby until it is born, called a fetus.

Humans usually have babies through a process called internal fertilization during sexual intercourse. In this process, the male releases semen that contains sperm into the female. If a sperm meets an egg, called an ovum, it creates a new cell called a zygote. This zygote moves to a place in the female’s body called the uterus, where it starts to grow. This growing period is known as pregnancy, lasting about nine months.

When the baby is ready, it is born through a process called childbirth. The baby then needs lots of care from adults. This care includes keeping the baby clean, comfortable, and fed. Feeding can happen through breastfeeding or with special milk called formula feeding. Babies depend on their caregivers for many months to stay healthy and happy.

Structure

Female

Main article: Human female reproductive system

The human female reproductive system includes organs inside and around the lower part of the body. It has three main parts: the vagina, which connects to the uterus; the uterus, where a baby grows; and the ovaries, which make eggs. The breasts help with caring for a baby but are not usually considered part of the reproductive system.

The vagina opens to the outside at a part called the vulva. The uterus connects to the ovaries through tubes called fallopian tubes. Each ovary holds many eggs. About every 28 days, a hormone causes an egg to be released. If the egg meets sperm, it can grow into a baby inside the uterus.

Male

Main article: Human male reproductive system

The male reproductive system includes organs that help make and deliver sperm. Sperm are made in the testicles, which are kept at the right temperature in a pouch called the scrotum. Other parts help produce fluids that go with the sperm and tools used to place sperm inside the female.

Boys also go through changes such as growing taller, deeper voices, more body hair, and broader shoulders. A key hormone in males is called testosterone.

Development

The way the human body grows and develops its reproductive system starts very early, even before a baby is born. Both boys and girls have the same basic building blocks that later become different organs depending on whether the child will grow up to be male or female.

Special tubes and structures in the body change in different ways to create the organs needed for each gender. Hormones, which are like chemical messages in the body, help guide this process to make sure everything forms correctly. Even though the male and female reproductive systems look very different when fully grown, they start from similar beginnings.

Reproduction

Further information: Human reproduction

Production of gametes

Main articles: Spermatogenesis and Oogenesis

Gametes are special cells made in the body that help create new life. They are made in the gonads through a process called gametogenesis. This process happens when certain cells go through meiosis to split their chromosomes into smaller parts.

In males, this process is called spermatogenesis and starts after puberty in the testes. The young sperm cells move to the epididymis, where they grow tails and learn to move. Each original cell makes four sperm cells.

In females, the process is called oogenesis and happens in the ovaries. It usually makes one mature egg cell and three smaller cells that aren’t used for making a baby. Scientists used to think that all egg cells in a female were made before birth, but new research shows that in some animals, more egg cells can be made after birth.

Both males and females have special ways to protect the DNA in their gametes to make sure it stays healthy for making new life.

Disease

Main article: Reproductive system disease

The human reproductive system can be affected by many different diseases, just like other parts of the body. These diseases fall into four main groups: genetic or congenital abnormalities, cancers, infections (which can sometimes spread through close contact), and problems caused by things in the environment, injuries, or other health issues. Common problems include difficulty with certain body functions and trouble having children.

Some reproductive diseases are signs of other health problems, and many have many possible causes, which makes them hard to sort into just one group. For example, there are conditions that affect men and women differently, and some diseases that are usually known for other symptoms can also cause issues with the reproductive system.