But for 74-year-old Andy McNicol, from Walsall, there's always been one person missing from the family album.
He had met John’s mother, Brenda, and two years into their relationship, she discovered she was pregnant.
After hearing she had given birth, he went straight to the hospital to see the baby but was not allowed into the ward.
Then aged 27, Mr McNicol was separated from his son John at birth on June 3, 1970, who was given up for adoption – despite it being against his father's wishes.
John's mother Brenda wouldn't let him get close enough to see his face, and his only memory is seeing a spot of red hair poking out of the blanket in the plastic cot on the maternity ward at Bath Royal United Hospital.
"I felt so helpless, he said. "The saddest day of my life without a doubt. I wanted to tell him – I didn’t leave you, you were given away son, if I had my way it would have never of happened.
"It was the very worst day of my life, as bad as any bereavement. It was the very worst day of my life, as bad as any bereavement.
"Desperate to stop the adoption, I went straight to the local registrar’s office, where I learned that my name wasn’t even on my son’s birth certificate.
"Under the section for father’s name, there was just a line. I told them that I was the baby’s dad, but they said that as we weren’t married, only the mother, Brenda, had the right to provide those details, and she had said the father was “unknown”."
As he wasn't able to marry Brenda before John's birth due to being separated but not yet divorced from his first wife – much to the dismay of her family as he had been conceived out of wedlock – she was forced to stop speaking to him.
Now, in an emotional episode of ITV's Long Lost Family, John has been tracked down living on the other side of the world in Australia and the pair have been reunited after 46 years apart.
The show – which is being screened tonight – helps people find lost members of the family wherever they are in the world.
Long Lost Family used a specialist intermediary to search for John – they discovered he still had the same name and had grown up in Weston-Super-Mare.
After 2013, there was no record of him living in the UK but after extensive searching, he was tracked down to be living on the other side of the world in Australia.
“Just for him to walk in and call him my son was the best day of my life without a doubt.
Show presenter Nicky Campbell met John at his home in New South Wales and was gobsmacked to discover that his father was looking for him.
While Davina McCall travelled to Walsall to let Mr McNicol know his son had been found. In an emotional reveal, he flabbergasted by the news and feels like they can have a new start.
After more than 46 years apart, the pair were re-united just outside Bath, the city where John was born.
Long Lost Family is on Wednesday at 9pm on ITV.