Frank Rooney asked to be tested as a possible donor the day his little boy John Paul was born with an extremely rare kidney problem.
He was aware of the shortage of kidneys for transplantation.
Three years later he got his wish. And just two weeks after the double surgery, father and son are recovering well.
Frank, 30, who owns his own business, said: "People always say you would do anything for your kids and it's true. When I think of the amount of pain he has gone through, two weeks of pain for me is nothing.
"I'd do it again if I had three kidneys."
The Evening Times first told in February 2011 how John Paul had been diagnosed with kidney problems in the womb.
John Paul, Frank and his partner Maryanne's first child, had to be delivered one month early so he could receive emergency medical treatment for his prune belly syndrome - a rare genetic disorder that affects the kidneys and bladder.
Babies with the illness, which is also called Eagle-Barrett syndrome, have no abdominal muscles or very weak abdominal muscles and can be born with extra wrinkled skin on their bellies.
The illness was picked up at Maryanne's 20-week scan and she had to attend hospital every week of her pregnancy.
Fluid had been building up in John Paul's body and damaging his renal system.
Since being allowed home at three weeks old, John Paul has needed round-the-clock care, including dialysis at home every night and weekly visits to Yorkhill Hospital.
It had been hoped that his condition, which affects just one in 40,000 births, would be managed by drugs but doctors quickly realised a transplant would be necessary.
Both Maryanne, who works for Arnold Clark, and Frank were tested for compatibility and Frank was found to be a 99% match.
Frank, who is from Hamilton, said: "I thought I would be able to do it immediately but they said we would have to wait until he was bigger.
"The process was a lot simpler than I thought. The tests are meant to take around nine months but I took lots of cancelled appointments so I had all the tests in seven weeks.
"Anyone can donate but health is a factor. They didn't want to make a patient out of me."
On April 16, Frank, who runs his own cleaning business, was wheeled into the operating theatre at Glasgow's Western Infirmary, for surgery to remove his right kidney, knowing his little boy was close by at Yorkhill hospital waiting for it.
He said: "I was more worried about Maryanne, knowing she would be worried about both of us.
"I was taken in about 8.15am and John Paul was taken in 45 minutes later.
"As soon as I woke up the nurses said to me, you might be a bit sore but the kidney you gave your son was working within half an hour. That took away the pain."
HE continued: "They took me to see him, to see the smile on his face was incredible.
"You could see instantly that he was a different boy. He's taken everything in his stride, he was always smiling but this time the smile told a different story.
"He will now be able to stay with his grandparents, to go on holidays. We tried not to keep him in bubble wrap but we had to keep him away from common colds, we had to be home at a certain time for dialysis. I'm feeling good, a bit tender but that's to be expected."
The shortage of organs has led to more people across the UK receiving organs from living donors. Although this involves carrying out major surgery, results are often very successful.
The couple have raised almost £5000 for Yorkhill Hospital to say thank you for the care their son has received so far.
Frank has given his full backing to the Evening Times' campaign for an opt-out transplant system. He is aware that John Paul may need one or even two more transplants in the future.
He said: "I think it's a great idea. I read a story about a man waiting 1000 days for a kidney, that is why I asked to be tested. I think (organ donation) should be mandatory, as well as donating blood.
"I've been a registered donor since I was 18. I told the doctors if they weren't able to use my kidney for John Paul, that I wanted someone else to benefit."
Peter Storey, of Kidney Research UK, said: "There are just not enough kidneys available for transplant; around 550 people in Scotland are waiting for a kidney but less than half of them will receive one.
"The best chance of finding a match for a transplant will be from an immediate family member, such as a parent, child or sibling."