The body and sex

Cancer and its treatment can cause physical changes that may affect your sex life. Find out about the body and what happens during sex.

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About the body and sex

Cancer or its treatment may cause changes to your body that can affect your sexual well-being.

This information is about the parts of the body involved in wanting and having sex. It also explains what happens to the body during sex. You may find it helpful when reading our information about side effects or talking to your healthcare team.

If you have had gender-affirming surgery or are intersex, your body may be different in some ways to what we describe here. If you cannot find the right information for you, a trans and non-binary friendly sexual health and well-being service may be able to help. You can check whether this is available on Tranzwiki. Or you could contact the UK Cancer and Transition Service (UCATS) for more information.

The brain and nerves

The brain controls how the body works. For example, it controls breathing, blood pressure and heart rate. It also controls how we understand the world around us, and our emotions, thoughts and memories.

Nerves are cells that send messages between the brain and different parts of the body. They give the brain information about what is happening in an area. They also allow the brain to send instructions to that area of the body. For example, nerves allow the brain to tell your eye muscles to move and make the pupils smaller in bright light – or to send more blood to the sex organs when aroused.

When it comes to sex, the brain and nerves tell you what feels good. This depends on what you are feeling physically. It also depends on things such as your emotions and memories. Your brain and nerves also help control what happens to your body during sex.

The female pelvic area

The pelvis is the area between the hips and below the belly button. For women, trans men and other people assigned female at birth, the sex organs you were born with include:

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

Together, these are called the reproductive system. This is the system involved in getting pregnant and giving birth.

Female pelvic area

The female reproductive organs shown in cross section. Labels include womb, bladder, ovary, fallopian tube, vagina, urethra and pelvic floor muscle.
Image: he image shows a side view of a female the body from the lower abdomen to the upper thigh. It shows the structures and organs in the pelvis. There is a smooth flat bone at the front of the pelvic area. This is the pubic bone. At the back of the body, a line of connecting bones are shown following the curve of the back down. These are the spine. A curved ‘hammock’ shape connects the pubic bone and the end of the spine. This is the pelvic floor muscle. There are three small openings into the pelvis between the legs. The opening closest to the back of the body is called the anus. It leads up through the pelvic floor muscle into a tube shaped space called the back passage or rectum. The opening closest to the front of the body leads up through the pelvic floor muscle through a short narrow tube called the urethra. This leads into a rounded hollow organ called the bladder. The opening in the middle leads up through the pelvic floor muscle through a longer tube called the vagina. This leads into a hollow organ with thick walls called the womb or uterus. The lowest part of the womb is highlighted where it meets the vagina. The highlighted area is called the cervix. The womb sits behind and over the bladder. At the top of the womb, a thin short tube is shown leaving the womb. This is a fallopian tube. It leads to a small solid oval organ. This is an ovary. Above the bladder and womb, a large space is shown. This space fills the front half of the body. A thin lining is shown covering the walls of the space. This lining is the peritoneum.

The brain controls the reproductive system using hormones (chemical messengers). These hormones are made in the ovaries and in areas of the brain, such as the pituitary gland. The hormones affect your:

  • periods (menstruation)
  • ability to get pregnant (fertility)
  • interest in sex – this is called your sex drive or libido.

Eventually, the ovaries stop making hormones. This is called the menopause. It usually happens between the ages of about 45 and 55. Changing levels of hormones during the menopause can cause symptoms that include lack of interest in sex and vaginal dryness.

Outside the body and between the legs is the vulva. The skin forms 2 large outer folds and 2 smaller inner folds around the opening to the vagina. At the front of the vulva is the outer tip of a sensitive structure called the clitoris. The rest of the clitoris sits further back and inside the body.

The vulva

Diagram of the vulval area between the legs. Labels include the clitoris, mons pubis, labia minora and majora urethra, vagina, perineum and anus.
Image: The illustration shows the vulval area between the legs. At the top of the diagram, between each leg, is the mons pubis. Below this is the clitoris, which sits above the urethra and the vagina. They are all within the inner fold of skin called the labia minora, which are within the outer fold of skin called the labia majora. The anus is below the vagina at the bottom of the diagram. The area between the vagina and the anus, called the perineum, is also shown.

The pelvis also contains:

  • the bladder and urethra – the system that removes urine (pee) from the body
  • the lowest end of the bowel, including the rectum and anus – the system that removes stools (poo) from the body
  • a set of supporting muscles called the pelvic floor muscles.

The male pelvic area

The pelvis is the area between the hips and below the belly button. For men, trans women and other people assigned male at birth, the sex organs you are born with include the:

  • penis
  • testicles
  • prostate.

Outside the body, the penis hangs from the front of the pelvic area. Behind the penis, 2 testicles hang below the body in a pocket of skin called the scrotum. A gland called the prostate sits inside the body in the pelvis.

Together, the penis, testicles and prostate gland are called the reproductive system. This is the system that allows you to make sperm and start a pregnancy.
The brain controls the reproductive system using hormones (chemical messengers). These hormones are made in the testicles and in areas of the brain, such as the pituitary gland. The hormones control:

  • sperm production
  • your ability to get and keep an erection
  • your interest in sex – this is called your sex drive or libido.

The pelvis also contains:

  • the bladder and urethra – the system that removes urine (pee) from the body
  • the lowest end of the bowel, including the rectum and anus – the system that removes stools (poo) from the body
  • a set of supporting muscles called the pelvic floor muscles.
The male reproductive organs shown in cross section. Labels include bladder, prostate, penis, seminal vesicles, pelvic floor muscle, testicle and anus.
Image: A cross-sectional illustration showing the positions of the male pelvic organs including the bladder, urethra, prostate gland, rectum and anus. The image is from the side with the body facing to the left. On the left of the image there is a bone called the pubic bone. This is at the front of the body beneath the bladder and above the root of the penis. At the back of the body are the bones that make up the spine. A layer of muscles called the pelvic floor muscles are attached to the pubic bone at the front of the body and go to the last bone in the spine at the back of the body. This looks a bit like curved hammock shape. The bladder is in the centre of the image. A tube called the urethra runs from the bottom of the bladder through the prostate gland directly beneath the bladder, through the pelvic floor muscle and then through the penis to the opening at the tip of the penis.

 

Other sensitive areas

Most people also have other areas of the body that are sensitive to touch. These can be an important part of their sex life. They are sometimes called erogenous areas. Sensitive areas are different for each person. They may include:

  • the chest area, breasts or nipples
  • the back of the neck
  • the anus and rectum
  • the backs of the knees, buttocks or inner thighs.

What happens to the body during sex

Your body may go through various stages. This is sometimes called the sexual response.

  • Arousal – this is when you feel ‘turned on’ and ready for sex. You may feel aroused by thinking about sex, seeing someone you are attracted to, touching someone or being touched by someone. During this stage, your brain usually sends messages to the nerves in your pelvis and increases the blood flow to these areas. This can cause the vulva and vagina to swell and become wet, or the penis to become hard (erect).
  • Plateau – this is a stage of arousal where your body is very sensitive to touch.
  • Orgasm – this is a feeling of intense pleasure that may happen after being aroused. It is also called climax or ‘coming’. Muscles in different areas of your body contract. Fluid (ejaculate) may release from the tip of the penis. Orgasm can happen by touching the penis or clitoris. Some people can reach orgasm without this or by touching other parts of the body.
  • Resolution – the stage after arousal and orgasm. The physical changes in the body go back to normal. Some people can become aroused and orgasm again straight away. Others may not want to or be able to for a time. In general, this takes longer as we get older.

The sexual response is different for each person. What feels good for you depends on:

  • how your brain responds to a physical sensation
  • how you feel emotionally
  • your memories, beliefs and experiences.

Arousal

This is when you feel ‘turned on’ and ready for sex. You may feel aroused by thinking about sex, seeing someone you are attracted to, touching someone or being touched by someone. During this stage, your brain usually sends messages to the nerves in your pelvis and increases the blood flow to these areas. This can cause:

  • the vulva and vagina to swell and become wet
  • the penis to become hard (erect).

Plateau

This is a stage of arousal where your body is very sensitive to touch.

Orgasm

This is a feeling of intense pleasure that may happen after being aroused. It is also called climax or ‘coming’. Muscles in different areas of your body contract. Fluid (ejaculate) may release from the tip of the penis. Orgasm can happen by touching the penis or clitoris. Some people can reach orgasm without this or by touching other parts of the body.

Resolution

This is the stage after arousal and orgasm. The physical changes in the body go back to normal. Some people can become aroused and orgasm again straight away. Others may not want or be able to for a time. In general, this takes longer as we get older.

Sexual response is different for each person. What feels good for you depends on:

  • how your brain responds to a physical sensation
  • how you feel emotionally
  • your memories, beliefs and experiences.

About our information

  • References

    Below is a sample of the sources used in our sex and cancer information. If you would like more information about the sources we use, please contact us at cancerinformationteam@macmillan.org.uk
    Katz A, Agrawal LS, Sirohi B. Sexuality after cancer as an unmet need: addressing disparities, achieving equality. American Society of Clinical Oncology Educational Book. 2022 Apr; (42):1-7. doi:10.1200/edbk_100032
    Sousa Rodrigues Guedes T, Barbosa Otoni Gonçalves Guedes M, de Castro Santana R, Costa da Silva JF, Almeida Gomes Dantas A, Ochandorena-Acha M, et al.. Sexual dysfunction in women with cancer: a systematic review of longitudinal studies. International Journal of Environmental Research and Public Health. 2022 Sep 21;19(19):11921. doi:10.3390/ijerph191911921
    Wittmann D, Mehta A, McCaughan E, Faraday M, Duby A, Matthew A, et al. Guidelines for sexual health care for prostate cancer patients: recommendations of an international panel. Movember. 2022. Available from: https://truenorth.movember.com/images/assets/SexualHealthGuidelines.pdf

  • This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been approved by members of Macmillan’s Centre of Clinical Expertise.

    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.

Related pages

Date reviewed

Reviewed: 01 March 2024
|
Next review: 01 March 2027
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.

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