Alex Powell made the decision to freeze his sperm after being diagnosed with a rare cancer at the age of 15.

A baby boy has been born from the world's oldest sperm - after his dad froze it 23 years ago.

Xavier Powell, just six-months-old, has even made it into the Guinness World Records thanks to his father's decision two decades ago.

Alex Powell, from Australia, was diagnosed with Hodgkin's lymphoma at the age of 15.

He was told he needed to start chemotherapy immediately and made the decision to have his sperm frozen as the treatment was likely to leave him infertile .

That was 23-years ago and now the dad is celebrating his son's first few months of life with his wife Vi.

It was Alex's stepmum who convinced him to go ahead with the procedure after worrying about the effects of cancer treatment on her stepson's body.

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Two decades later, Alex met his wife Vi and the loved-up pair decided they would like to have children.

In 2013, the couple began IVF in the hope that they would be able to conceive a baby.

Alex admitted he was nervous before the start of treatment, adding: "When they bring those guys out, what's going to happen? Are they all going to turn left?"

It took one year of IVF for Xavier to be conceived and he was eventually born on June 17, 2015.

Alex told Nine News: "For me, it's that sort of feeling in life you want to relive every moment if you can.

Before Xavier, a baby had previously been conceived in the UK using sperm frozen for 21 years.

There is technically no upper limit on how long sperm should be stored for but it is usually between seven and 10 years.