Dr. Charles Smith waits to deliver testimony at a public inquiry into his work led by Justice Stephen Goudge in Toronto in January 2008. (Adrian Wyld/Canadian Press)

Ontario's highest court has acquitted a woman who was convicted in 1999 of killing her infant son based in part on evidence of now disgraced pathologist Dr. Charles Smith, calling the case a miscarriage of justice.

Both the defence and Crown called for Sherry Sherret-Robinson's acquittal at a hearing Monday in the Court of Appeal for Ontario.

The Crown said new expert evidence "conclusively refutes critical aspects" of Smith's opinion.

Smith had concluded the boy, Joshua, died of asphyxia and that his death was suspicious due in part to a skull fracture and neck hemorrhages.

But Dr. Michael Pollanen, Ontario's chief forensic pathologist, and other experts found there was no skull fracture and the neck hemorrhages were in fact caused by Smith during the autopsy.

The experts concluded there was no basis in the pathology to support Smith's inference the baby was deliberately smothered or suffocated, but that it can't be ruled out.

Instead, Pollanen suggested, the autopsy findings and the fact that Joshua had numerous layers of blankets under, around and on top of him, "reasonably support the conclusion that death occurred by an accidental asphyxial means in an unsafe sleeping environment."

A report on pediatric forensic pathology from Justice Stephen Goudge last year found the failings of the "arrogant" Smith, once considered the dean of his profession, and his bosses were at the heart of several miscarriages of justice.

Sherret-Robinson had initially pleaded not guilty to infanticide, but the Crown and her lawyer drafted an agreed statement of facts that said she smothered Joshua, causing his death, and she was found guilty in a Belleville, Ont., court in 1999.

In an affidavit filed with the Court of Appeal, Sherret-Robinson says she has always wondered if she put too many blankets around Joshua that night and now will have to live with the knowledge that this probably led to his death.

"I will never forget the terror I felt when I reached down to pick him up and discovered that he was blue and his little body was completely stiff," she writes.

After the police arrived, the next thing she remembers is sitting in the emergency room, hugging a picture of Joshua and sobbing.

"Eventually the doctors came and told me he had died, and let me hold him to say goodbye," Sherret-Robinson writes.

"I sang him a lullaby and refused to let go of him. Even to this day I cannot get that image out of my head."

Goudge referred to Sherret-Robinson's case in his report, saying Smith "inappropriately" formed his opinion using matters outside the pathology, such as statements Sherret-Robinson had made one month before the death that she was depressed and was going to smother her baby.