A British man is thrilled to be a father for the third time - a few years after the birth of his second grandchild and 11 years after freezing his sperm.

Malcolm Lawrence, 67, of South Wales told the British Daily Mail that when he and his 31-year-old wife married 11 years ago, he was unable to father a child the natural way and his wife was too young for in vitro fertilization (IVF).

He decided to freeze a sperm sample that was stored in a hospital over the next decade.  Last year, his wife underwent a course of IVF and got pregnant using the frozen sperm.

"It was a real shock," he told the newspaper after the recent birth of his daughter, Cerys-May.  "I still can't believe it has happened."

Lawrence has adult children from his previous marriage, and it's unclear why Lawrence was unable to naturally become a father after his second marriage.  Age has little bearing on male fertility, according to experts.

"Men make sperm until they die, and age doesn't matter," said Dr. Jamie Grifo, program director of the NYU Fertility Center in N.Y.

There is some evidence suggesting that there is an increased risk of autism in children born to fathers older than 50, but Grifo said the findings are controversial and not yet proven.

One of the main reasons men opt to freeze sperm is if they are diagnosed with cancer, Grifo said, since certain treatments can affect sperm quality.  Once sperm is frozen, it remains viable for years.

"Frozen sperm works as well as real sperm in an IVF lab," he explained.  "It's still effective."

It has no impact on a woman's reproductive potential, Grifo added.  If a woman has trouble getting pregnant, whether the sperm is frozen or fresh has no bearing on her ability to have a child.

Lawrence said he's suffered 12 heart attacks and also lives with a bad back and a lung condition, but he didn't let his health - or the naysayers who said he was too old and too sick - get in the way of the couple's desire to have a family.

"I've proved them all wrong by giving my wife what she always wanted - a child of her own," he said.