The reproductive system

The parts of your body that help you get pregnant or make someone pregnant are called the reproductive system.

The female reproductive system

For women, trans men and other people assigned female at birth, the reproductive system you are born with includes:

  • 2 ovaries
  • 2 fallopian tubes
  • the womb (uterus)
  • the cervix
  • the vagina.

The female reproductive system

Female reproductive system no lymph nodes
Image: Lower abdomen, pelvis and the top of the legs from the front. A narrow opening is shown between the legs. This leads into a narrow space shown inside the pelvis. This space is called the vagina. Above the vagina the space narrows until both sides almost touch. Then it opens again to form a hollow pear shaped organ called the womb. The surfaces of the two sides are highlighted where they narrow between the vagina and the womb. The highlighted area is the cervix. At either side of the upper end of the womb are 2 small solid oval shapes. These are the ovaries. They are connected to either side of the womb by narrow tubes called the fallopian tubes.

To get pregnant and give birth to a baby, your body needs:

  • to produce a supply of healthy eggs
  • a healthy womb
  • the right hormone levels.

Eggs develop in the ovaries, in small fluid-filled sacs called follicles. Once a month, 1 of the ovaries usually releases an egg. This is called ovulation.

Ovulation starts during puberty. It usually continues until the menopause (see below). Hormones help control this process. These are released by the ovaries and a small gland at the base of the brain called the pituitary gland.

To start a pregnancy, the egg needs to be fertilised. This happens when it joins with a sperm. Sperm are made by the reproductive system of a man or person assigned male at birth.

The egg leaves the ovary and travels along the fallopian tube. If it meets and joins with a sperm here, it may develop into an embryo. The embryo continues to travel to the womb, where it can settle itself into the womb lining. The embryo stays in the womb and grows into a baby.

Every month, hormones from the ovaries prepare the lining of the womb for an embryo. If the egg is not fertilised, the hormone levels drop. The womb lining then comes out through the vagina. This is called a monthly period.

You can start a pregnancy by:

Natural menopause

Women, trans men and other people assigned female at birth are born with lots of eggs stored in the ovaries. With age, the number of eggs decreases and hormone levels change.

When very few eggs are left, the ovaries stop releasing an egg every month, and monthly periods stop. When periods have stopped for more than 1 year, this is called the menopause.

Symptoms of the menopause include:

  • hot flushes and sweats
  • vaginal dryness
  • mood swings
  • feeling emotional or anxious
  • difficulty sleeping
  • a low sex drive.

The menopause happens naturally because of age. Usually, this is between the ages of 45 and 55. Natural menopause is permanent.

Other causes of menopause

The menopause and menopausal symptoms can happen for reasons other than age.

Sometimes they are a side effect of cancer treatment. Depending on the type of cancer treatment, you may have either of the following:

  • Temporary menopause

    Periods may stop during treatment and start again after. You may also have some menopausal symptoms for a time. These may get better gradually after treatment ends.

  • Permanent menopause

    Some cancer treatments cause permanent damage to the ovaries. You may have no more periods and continue to have menopausal symptoms after treatment ends. This is called early menopause or premature ovarian insufficiency (POI).

Some other medications and health conditions can affect your hormone levels and cause menopausal symptoms. Always talk to your doctor if you have symptoms that are ongoing, unexplained or unusual for you. They can check your hormone levels and give you advice.

Coping with menopausal symptoms can be hard. Ask your cancer doctor or specialist nurse for advice about treatments that can help. We have more information about coping with menopausal symptoms.

The male reproductive system

For men, trans women and other people assigned male at birth, the reproductive system you are born with includes the testicles, penis and prostate gland. To start a pregnancy, your body needs to produce healthy sperm.

The male reproductive system

The male reproductive system
Image: Side view of a body from the lower abdomen (tummy area) to the top of the thigh. The penis is shown curving down and away from the front side of the body. A small oval shape is shown hanging in a pocket of skin behind the penis and below the body at the inner thigh. This is a testicle. Inside the body, behind and higher up than the penis is a hollow, rounded shape. This is the bladder. A narrow tube runs from the lower end of the bladder, down through the penis to the tip of the penis. Under the bladder and around this tube is a smaller, rounded shape. This is the prostate gland. A second tube runs from the testicle up inside the body to join the prostate gland.

The testicles start to make and store sperm during puberty. Chemical messengers called hormones help control this process. Hormones are produced by:

  • a small gland at the base of the brain called the pituitary gland
  • the testicles.

The testicles testes produce the hormone testosterone. Testosterone also controls sex drive and erections (the penis becoming hard).

To start a pregnancy, 1 sperm needs to reach and join with an egg. This is called fertilisation. Eggs are made by the reproductive system of a woman or person assigned female at birth.

You can start a pregnancy in the following ways:

  • Ejaculating (coming) during vaginal sex – when you ejaculate, the fluid that comes out of the penis through the urethra is called semen. Semen is made up of fluid from the prostate gland and sperm from the testicles.
  • Using fertility treatments such as IUI or IVF – these treatments use samples of collected sperm.

About our information

  • References

    Below is a sample of the sources used in our fertility and cancer information. If you would like more information about the sources we use, please contact us at

    Lambertini M, Peccatori FA, Demeestere I, et al. Fertility preservation and post-treatment pregnancies in post-pubertal cancer patients: ESMO Clinical Practice Guidelines. Annals of Oncology, 2020; 31, 12, 1664-1678.

    National Institute for Health and Care Excellence. Fertility problems: assessment and treatment. [Internet]. 2017, Available from [accessed November 2022].

  • Reviewers

    This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer. It has been approved by Chief Medical Editor, Professor Tim Iveson, Consultant Medical Oncologist.

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

The language we use

We want everyone affected by cancer to feel our information is written for them.

We want our information to be as clear as possible. To do this, we try to:

  • use plain English
  • explain medical words
  • use short sentences
  • use illustrations to explain text
  • structure the information clearly
  • make sure important points are clear.

We use gender-inclusive language and talk to our readers as ‘you’ so that everyone feels included. Where clinically necessary we use the terms ‘men’ and ‘women’ or ‘male’ and ‘female’. For example, we do so when talking about parts of the body or mentioning statistics or research about who is affected.

You can read more about how we produce our information here.

Date reviewed

Reviewed: 01 April 2023
Next review: 01 April 2026
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

This means it is easy to use, up-to-date and based on the latest evidence. Learn more about how we produce our information.