It can be difficult to predict if cancer treatment will affect your fertility or if it will return to normal after treatment. Even if your chances of becoming infertile are low, you may be referred to a fertility doctor before treatment starts, and you may be advised to store (bank) sperm.

Freezing and storing sperm is a safe technique that has been successfully used for many years. There is no lower age limit for sperm banking, as long as you have reached puberty and are producing sperm.

Your sperm can then be used in the future to help you and a partner try to have a child. Your fertility doctor can discuss which fertility treatments may help in your situation.

Most fertility clinics will make sure that you are seen before cancer treatment starts. But some men don’t have time to store sperm as treatment needs to start straight away. Storing sperm after treatment starts is usually not advised. Your cancer doctor or specialist nurse can discuss this with you.

Some religions may not agree with certain fertility treatments. If this is an issue for you, you may want to discuss it with your partner, family or religious adviser. You can also talk in confidence with a trained counsellor or social worker.

Before sperm samples are stored, you’ll be asked to sign a consent form that explains how your sperm will be used. If you are under 16, your parent or guardian may be asked to sign some forms too.

You will have some blood taken to test for infectious diseases such as hepatitis and HIV. This is standard procedure for all men storing sperm.

Usually, you provide sperm samples by masturbation in a private room in the fertility clinic. If you have a partner, they can be with you if you want. You may find this difficult and embarrassing, but the fertility clinic staff will be sensitive and are used to this. Sometimes it may be possible to collect a sample at home and take it to the clinic. This can only be done if you can keep the sample warm and deliver it to the fertility clinic within 30 to 45 minutes.

If possible, you provide two or three samples over a week. But if you can only give one sample before cancer treatment starts, that may still be enough. You are usually advised not to have sex or masturbate for a couple of days before collecting each sample. This allows more sperm to be collected.

Some men are unable to produce samples by masturbation. But it may be possible for a specialist doctor to take a small amount of sperm straight from the testicle. You will have a local anaesthetic and sedation, or a general anaesthetic, to make it more comfortable. Sperm extraction can be done in two ways:

• Percutaneous epididymal sperm aspiration (PESA) – a fine needle is passed into the testicle to withdraw (aspirate) some fluid.
• Testicular sperm extraction (TESE) – tiny bits of tissue (biopsies) are taken from the testicles.

The fluid or tissue that’s removed is looked at under a microscope in a laboratory. Any sperm is removed, frozen and stored for future use.

This may be done before cancer treatment starts, or sometimes after treatment for men who haven’t had sperm stored.

If you have retrograde ejaculation, you still produce sperm. But your sperm and semen go backwards into your bladder instead of out of your penis when you orgasm.

Sometimes doctors are still able to collect your sperm. You will be given a drink that makes your urine less harmful to your sperm. You will be asked to pass urine and then masturbate. After you ejaculate, you will have to pass urine again. The sperm is quickly collected from the urine, prepared and stored.

The NHS provides sperm storage for men with cancer. But in private clinics you may have to pay for it yourself. Sperm is usually stored for 10 years. But for men affected by cancer, it can be stored for up to 55 years. The staff at the fertility clinic will explain this to you.

Your sample will be frozen and stored in a tank of liquid nitrogen. This is called cryopreservation.

Even if the number of sperm is low, your sample can still be frozen, stored and used later.

Researchers are looking into removing and freezing testicular tissue from boys who haven’t reached puberty. It is hoped that the tissue can later be re-implanted to preserve their fertility. Researchers are also looking into whether they can produce sperm from these cells in a laboratory. These techniques are experimental and doctors don’t yet know the risks involved. Only a couple of centres in the UK offer this service.