Lydia thought her baby's coffin felt too light. When she checked, it was empty.

It’s been 42 years since the funeral of Gary Paton. His mother, Lydia Reid, is still trying to find out what happened to his body.

Last month, the grieving mother watched as her baby son’s grave in Edinburgh was exhumed. When the coffin was opened, it was revealed to be empty. Reid had suspected as much, ever since the day of the funeral in 1975, when she felt the coffin was too light to have a baby inside.

Reid is now demanding that DNA testing be done on tissue samples taken from Gary’s body after his death, to prove that the samples really came from him. Now she’s wondering if her baby perhaps didn’t die, all those years ago.

“Is my son alive?” Reid said to The Washington Post. “I have to look at all possibilities.”

The mystery of baby Gary is tied in with a decades-long body parts scandal that has rocked the UK and even Australia. Thousands of parents who lost a baby or a child, anywhere from the 1950s to the 1990s, later discovered that their organs had been stolen by hospital staff before their burial.

But Gary’s story is more complicated than most.

Reid was 26 and a mother-of-two when she gave birth to Gary. She went into labour six weeks early and he was delivered by caesarean. He was put into a special care unit, and Reid would visit him, holding his fingers and speaking lovingly to him.

When Gary was six days old, he was transferred to another hospital. He underwent surgery to remove a catheter that a doctor had left in him. But Gary’s heart stopped three times on the operating table, and hospital staff told Reid that he had traumatic brain damage and would never recover. When they suggested taking him off life support, she agreed.

Oddly, Gary was later put back on life support. During the night, Reid was visited at home by police and told her son had died. She asked to see the body at the funeral home, so she could bury Gary in a shawl her mother had crocheted. The undertaker refused. Eventually, the body of a “blond and big” baby was brought out, looking nothing like Gary, who was small and dark-haired.

“I objected, but they said I was suffering from post-natal depression,” she later told The Telegraph.

At the funeral, Reid carried her son’s coffin to the grave. She felt sure it wasn’t heavy enough to have a body in it. Once again, she was told she was wrong.

For decades afterwards, Reid visited the grave, week after week, to be near her son. But he was never there.

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News broke in 1999 that hospitals in the UK had been secretly taking organs from deceased patients, mostly babies, since the 1950s. It was eventually found that more than 100,000 organs, body parts and even bodies of stillborn babies had been taken and stored. Scientists defended the practice, some claiming it was done for “research purposes”, and others being unable to understand why parents “got so bothered by a corpse”. Parents reported being told by hospitals that they weren’t informed “for our own good”.

The practice wasn’t just confined to the UK. In 2005, the South Australian government settled a lawsuit with more than 100 parents whose babies’ hearts, brains and other organs were removed during autopsies without their consent and stored in hospitals for decades.

When the scandal hit Scotland, Reid started asking questions. The hospital told her Gary’s organs hadn’t been taken, but when she got her hands on Gary’s medical records, she found out they had. She joined forces with other parents. They began fighting to get their babies’ organs back and to bring in new laws to stop anything similar happening again. Reid was even arrested after chaining herself to the Royal College of Surgeons.

Some parents got their babies’ organs back, but Gary’s were never found. Then the exhumation last month, done by forensic anthropologist Professor Dame Sue Black, proved Gary’s body had never been in the coffin.

“I wanted to be wrong,” Reid told the BBC. “I wanted to be called a stupid old woman. But the minute Sue lifted the shawl out of the ground, I knew there was nothing in it. Nothing.”

Now all Reid has are tissue samples, supposedly taken from her son after his death.

“They are the only evidence that we know of that is still in existence,” Reid told the Daily Record earlier this week. “I want them tested for DNA as I want to know if there is any part of my son there.”

After 42 years, Reid deserves to know the truth.