Cancer patients are not being offered the chance of fertility treatment that they should be, doctors say.
It means they risk the possibility of being left infertile by their cancer care, without the safety net of stored sperm or embryos.
Mr Townsend was diagnosed with testicular cancer in 2003
Dan Townsend was left reeling when he was diagnosed with testicular cancer in 2003.
He was told he would face months of chemotherapy treatment followed by surgery.
He said: "I was only 22 and it hit me hard. Not surprisingly the risk of infertility was pretty low down on my priorities and all I remember the doctors doing is shoving a leaflet into my hand.
"However, one day I started to look on the internet and realised there was a very real risk I could be left infertile.
"It got me worried and I began to find out about what help was available."
In the end, Mr Townsend, from Richmond, in south London, had some sperm frozen by a local NHS clinic.
It means he will have a chance of having children if he has been left infertile by the treatment. Research has shown that one in four testicular cancer survivors may have fertility problems.
He said: "I was young and I didn't have a girlfriend at the time so children was not something that was on my mind.
"But I guess I am the sort of person who looks into these things and I am glad I did.
"I am 26 now and have a long-term girlfriend, so having children is something I am beginning to think about more."
Mr Townsend, who works at London City Airport, is yet to find out if he has been left infertile. Cancer patients are advised to wait several years after the end of their treatment so they can get the most accurate test.
He added: "The great thing is that I don't really need to worry about it. If I am infertile, I know I have the stored sperm. I am so glad I went to the clinic.
"I think a lot of people probably don't consider these things when they are diagnosed with cancer, especially if they don't get the advice from doctors.
"Much more needs to be done. In the meantime my advice to anyone would be to look into the consequences of their treatment and take the necessary precautions."
A Cancerbackup helpline - 0808 800 1234 - is available for information or support.