Genetics may free a woman convicted of killing her 4 babies and help other parents explain the unexplainable

Updated 0430 GMT (1230 HKT) March 20, 2021

(CNN)Kathleen Folbigg has spent the past 18 years in prison for one of the most horrific crimes imaginable: killing all four of her babies.

But new scientific evidence suggests that's not what happened.
Genomic testing shows at least two of the Australian's babies likely died from a previously undiscovered genetic mutation that led to heart complications -- meaning she may have been wrongfully imprisoned for almost two decades.
The finding has prompted 90 scientists -- including two Australian Nobel Laureates -- to ask the governor of New South Wales to pardon Folbigg and let her walk free. If that happens, Folbigg's case will be one of the worst miscarriages of justice in Australian history.
The ramifications don't end there.
While scientists are still learning about the causes of sudden infant death syndrome (SIDS) -- an umbrella term for when children die suddenly from unexplained causes -- the findings in Folbigg's case may help other parents who are grieving the unexpected loss of their own children.

Early years

Right from the start, Folbigg's life was marred by tragedy. When she was 18 months old, her father stabbed her mother to death and served 15 years in prison for murder before being deported to England. She was a disruptive child with behavioral issues that one medical officer said could indicate she was abused as a baby by her father, according to a 2019 inquiry into Folbigg's convictions.
In the late 1980s, she married Craig Folbigg, who she had met at a disco in the Australian city of Newcastle. They had their first child when she was 21, a boy named Caleb.
Kathleen Folbigg leaving Maitland Court after being refused bail on March 22, 2004.
"(She) described herself as feeling completed, with a husband, home and a baby," the inquiry noted.
Then, when he was just 19 days old, Caleb died. The cause of death was given as SIDS -- essentially, the absence of evidence of any other cause.
Folbigg soon fell pregnant again, and in 1990 she had another son, Patrick. Tests showed he was normal and healthy. But at four months, he had an unexplained ALTE, an apparent life-threatening event, that left him with brain damage and seizures. Four months later, he died as a consequence of seizures.
Her third child, Sarah, died age 10 months -- her cause of death was listed as SIDS. When her fourth daughter, Laura, died age 18 months on March 1, 1999, police started investigating.
The couple's marriage broke down. After Folbigg left, her husband found her diary and read an entry that he said made him want to vomit. He took the diary to police on May 19, 1999, according to the inquiry.
On April 19, 2001, Folbigg was arrested and charged with four counts of murder.
Her childhood best friend Tracy Chapman describes Folbigg as a caring animal lover who was a "really good mom." But at trial in 2003, the prosecution argued Folbigg had smothered her children. There was no conclusive forensic proof -- instead, the prosecution relied on a maxim credited to British pediatrician Roy Meadow: "One sudden infant death is a tragedy, two is suspicious and three is murder, until proven otherwise."
The prosecutor compared the chance of the children dying of natural causes to pigs flying.
"I can't disprove that one day some piglets might be born with wings and that they might fly. Is that some reasonable doubt? No," the prosecutor told the jury during the 2003 trial. "There has never ever been before in the history of medicine that our experts have been able to find any case like this. It is preposterous. It is not a reasonable doubt. It is a fantasy and, of course, the Crown does not have to disprove a fanciful idea."
The prosecution pointed to Folbigg's journals, which they said contained virtual admissions of guilt.
"I feel like the worst mother on this Earth, scared that (Laura) will leave me now, like Sarah did. I knew I was short tempered and cruel sometimes to her and she left, with a bit of help," Folbigg wrote in one. "It c