Around 1,500 teens develop cancer in the UK each year

The charity Teenage Cancer Trust questioned 450 teenagers at a meeting in Sherwood Forest last weekend.

Just one in three said they were told their treatment could cut their chances of having children later in life.

The charity urged doctors and nurses to ensure young people are made aware of their options - such as freezing eggs or sperm - before having treatment.

Chemotherapy and radiotherapy can leave male and female patients sterile.

Freezing eggs or sperm before treatment can allow cancer patients to try to have children later in life.

Life choices

However, this survey suggests many teenagers are not being given that choice.

The poll also found that of those who were given the option, they were told too late. Their treatment had already started.

The vast majority of doctors do discuss it with them Dr Hamish Wallace, Royal Hospital for Sick Children, Edinburgh

In addition, almost half of those who did have counselling to inform them of their options were not satisfied with it.

Simon Davies, chief executive of the Teenage Cancer Trust, said teenagers must be told of their options before their treatment starts.

"One might think fertility is not an issue for a 13 or 14 year-old teenager with cancer.

"Views expressed this weekend demonstrated that the opposite is true. Teenagers must be given a choice."

Dr Hamish Wallace, a consultant paediatric oncologist at the Royal Hospital for Sick Children in Edinburgh, said doctors discussed the issue with young patients.

"This is an important issue for these patients and it is something we discuss with them," he told BBC News Online.

"Bringing it up can be quite therapeutic because it shows them that somebody important thinks they're going to be around in a few years time."

Dr Wallace said some patients simply do not remember being told about the impact the treatment will have on their fertility.

"It is a very difficult time for them and they don't always remember what is brought up. But the vast majority of doctors do discuss it with them."

Cancer is the most common cause of natural death in teenagers. About 1,500 new cases are diagnosed each year in Britain.

Although young people develop specific types of cancer and have different medical and psychological needs, they are usually treated with children or adults.

Three-quarters of the teenagers questioned for the survey said they were in wards with young children or adults. Most would have preferred to be in wards with other adolescents.

Some 90% of teenagers questioned said they would be willing to travel up to two hours or more to receive treatment in a hospital that caters for teenagers and young adults with cancer.

Leukaemia, lymphoma and brain tumours are the most common types of cancer affecting children and teenagers.