Patrick Sloan, 60, who is due to retire in five years, thought his nappy-changing days were over.
“It was a huge surprise to discover I was going to be a dad again at my age,” a major newspaper quoted him as saying.
“But to find out that I was gaining another grandchild and my first great-grandchild at a similar time was unbelievable.
“I was worried people would be disapproving that I was going to be a father at an age where most people are retiring but everyone has been really pleased for us,” he said.
Sloan’s youngest son, Ethan, was born in March this year, followed shortly afterwards in June by his great-grandson, Mason, and then his grandson, Leonard, 12 days later.
Patrick, who has three grown-up children, and six grandchildren, said: “I have to admit that I had forgotten all about the sleepless nights and how everything has to revolve around the baby.
“It was a bit of a shock to the system at first but I wouldn’t swap being a new dad again for the world.
“Ethan is a little treasure and makes me smile every single day,” he added.
Sloan married his second wife Joanne, who is 21 years younger than him, in 2007. They met when they were working at the same hospital.
“We just hit it off and the age difference didn’t bother either of us.
“We didn’t talk about having any children back then. Joanne was concentrating on training to be a nurse and I was happy to be a doting granddad,” he said.
Joanne, 39, now a fully-qualified community mental health nurse, said that Sloan had already undergone a vasectomy but he had it reversed and eight months later she fell pregnant.