In order to understand any physical changes which occur because of your cancer or its treatment, it may be helpful to be reminded of the sexually sensitive areas of your body and how they respond to stimulation.

Women and their bodies
Men and their bodies
Stages of sexual arousal
Emotional effects on desire and sex drive
Physical effects on sexual response

Women and their bodies

A woman’s sex organs are mostly inside her body. Outside the body are the outer lips of the vagina, also known as the labia majora (see below).

The female external sex organs

When parted, these show the thinner, inner lips, the labia minora. These join at the front to cover the clitoris with a hood. The clitoris is usually sensitive to touch. The head of the clitoris, when not aroused, is about the size of a pea. All together, these form the vulva. Just beneath this, towards the vaginal opening, is the outlet for urine (the urethra). Further back still is the vagina itself. Behind the vagina is an area of skin called the perineum. Beyond that is the anus (opening to the back passage).

Inside a woman’s body lie the uterus (womb), the cervix (neck of the womb), the fallopian tubes and the ovaries (see diagram below).

Other sexual areas on the body include the breasts and nipples, which change in hardness and sensitivity when touched. Women also have other sensitive areas on their bodies which respond to direct touch, such as the nape of the neck, behind the knees, the buttocks and inner thighs. The sensitivity of these areas, known as erogenous zones, varies from woman to woman.

The womb and ovaries

Men and their bodies

In a man, the sexual organs are mostly outside the body and include the penis, testicles (testes or balls) and prostate gland (see diagram below). The end of the penis is covered by the foreskin, unless the man has had it removed by circumcision. The ridge on the underside of the head, called the frenulum, is usually the most sensitive part of a man’s penis. At the very top of the penis is a slit opening to the urethra, through which semen and urine pass.

At the base of the penis is a bag formed by wrinkly skin called the scrotum. Inside the scrotum lie the testicles. These produce sperm, which is then passed through tubes (vas deferens) to mix with other fluids to make semen.

The male sex organs

The other parts of a man’s sex organs are inside his body. The prostate gland lies deep in the pelvis and surrounds the first part of the urinary tube, the urethra, as it leaves the bladder (see the diagram). The prostate gland produces a fluid that mixes with the sperm to form semen, and helps create the intense sensations a man has during orgasm.

The penis, testicles and anus are erogenous zones. A man’s chest and nipples can also be sensitive, and his body may have other erogenous zones.

Sexual desire, also known as libido, is the name for interest in sex. Everyone's desire for sex is different and it can vary between men and women, and according to things such as age, events that happen in your life, your state of mind and changes in the body. For example, most women find their desire for sex changes throughout the menstrual cycle, when they are pregnant or breast-feeding and after the change of life (the menopause). Feelings and relationships can greatly influence the desire for sex in many people.

Excitement or arousal is the awakening of sexual feelings, when we feel 'turned on' and ready for sex. These feelings can be produced by simply seeing someone we fancy, being touched by or touching our lover, thinking about sex, or having our sexual areas touched. Arousal may, or may not, lead to orgasm.

Plateau is the phase where the body maintains a heightened state of arousal. The body is very sensitive during this phase.

Orgasm is the sexual climax and the feelings of intense pleasure that occur as areas of the body go into a series of rhythmic contractions. Some women can feel the uterus contract. Men ejaculate semen, unless they have had surgery (vasectomy) that affects the production of sperm.

Resolution is the phase that follows sexual arousal and orgasm. This is when the sexual changes in the body go back to normal. Men cannot usually be excited again for a while. However, many women can be aroused to orgasm again straight away. As people get older, they tend to lose the ability to become sexually excited repeatedly.

Emotional effects on desire and sex drive

Desire and sex drive make us act in a certain way when we are sexually aroused. Desire is not fixed, it changes over the years. Many things can reduce sexual desire, including:

tiredness
stress
mood changes (such as anxiety)
changes in contraception methods
feeling unhappy about our body
relationship problems
traumatic sexual experiences in the past
excessive drug or alcohol use
boredom with your sexual routine.

Desire for sex is greatly affected by our state of mind. If you are depressed, anxious or afraid about your cancer, its treatment or your relationship, you may find it more difficult to be sexually aroused.

Physical effects on sexual response

For the phases of sexual arousal to occur, certain systems in the body need to be working normally.

Physical arousal, plateau and orgasm will only happen if the body has a good blood supply, if the nerves to the pelvic area are working well and if the balance of hormones in the body is right.