CALGARY -- A lawyer for parents convicted in the meningitis death of their toddler son says the trial judge allowed the jury to be overwhelmed by medical evidence, but the Crown says the couple received a fair hearing.

The Alberta Court of Appeal heard arguments Thursday about the conviction of David and Collet Stephan in the 2012 death of their 19-month-old son Ezekiel.

They were convicted last year of failing to provide the necessaries of life to the boy, who they treated with natural remedies such as garlic, onion and horseradish rather than taking him to a doctor. Justice Rodney Jerke sentenced David Stephan to jail for four months and gave his wife three months of around-the-clock house arrest -- allowing her to only go out for medical appointments and church.

Defence lawyer Karen Molle said the trial judge did not properly exercise his gatekeeping function regarding expert evidence and allowed too many Crown experts to testify.

She said the amount of evidence from three doctors unfairly distracted jurors from the real question of whether the Stephans did anything different from any other reasonable parent.

"Doctors are educated and trained to identify meningitis, but the test is what a reasonable parent would do, not a medically trained professional," Molle said.

"We can't undo the impression that these doctors left on this jury. The jury is emotionally reacting to ... a week-long barrage of inflammatory and emotional evidence."

Molle also argued evidence from former chief medical examiner Anny Sauvageau was improperly restricted, as was that of Ezekiel's grandfather.

"This case became a battle of experts."

Crown prosecutor Julie Morgan argued the Stephans received a fair trial.

"The appellant is not challenging the medical findings. The issue is whether they received a fair trial, not whether their defence was ultimately successful," said Morgan.

Morgan said the jury heard evidence from both sides and came to the correct conclusion.

"Choices have consequences, only in this case the consequences were tragic. The appellants chose not to provide Ezekiel with proper medical attention," she said.

"The jury found a reasonable, prudent person in their situation would have foreseen medical attention was required and they failed to provide the necessaries of life. Sadly their choices did not leave medical professionals enough time to save Ezekiel and by the time they were involved it was too late."

The trial heard the little boy's body was so stiff he couldn't sit in his car seat, so the toddler had to lie on a mattress when his mother drove him from their rural home to a naturopathic clinic in Lethbridge, where she bought an echinacea mixture.

The Stephans never called for medical assistance until Ezekiel stopped breathing. He was rushed to a local hospital and died after being transported to Calgary Children's Hospital.

The Crown has said it will appeal the sentence once the conviction appeal is dealt with. It will argue the sentences aren't "proportionate to the gravity of the offence or to the degree of responsibility of the offender."