Paul and Zabeth Bayne say their 19-month-old daughter, who's in foster care, needs immediate medical attention. (CBC)

The parents of three children seized by the B.C. government in September 2007 say there is new evidence to suggest allegations that they shook and injured their baby girl were unfounded.

The children — two boys, now aged four and three, and a 19-month-old baby girl — were taken in September 2007 by the Ministry of Children and Family Development because the couple were suspected of shaking the girl and causing a head injury.

But the Surrey couple, Paul and Zabeth Bayne, obtained internal documents from the Ministry of Children and Family Development that suggest their daughter likely suffers glutaric aciduria, a rare disease often mistaken for child abuse.

Glutaric aciduria is a genetic disorder with varied symptoms, sometimes including bleeding and swelling of the brain.

Several doctors told CBC News on Thursday that the disorder has been mistaken for child abuse in other cases, and children suffering from it can die.

The Baynes, who hadn't heard of the condition until they obtained the ministry documents, said they want their daughter assessed and treated immediately.

Children and Family Development Minister Tom Christensen said Thursday he could not talk about this particular case.

Children and Family Development Minister Tom Christensen says foster children always get medical treatment when required. (CBC)

"But anytime a child is taken into care, they are provided medical attention when that is required," he said. "And we rely on the very top qualified pediatricians and others to advise us."

The couple said their children's foster mother emailed a social worker at the ministry two months ago, according to the documents they obtained.

"I noticed the baby sister was diagnosed with glutaric aciduria," the email said.

"I decided to do a Google search.… Children with glutaric aciduria are often misdiagnosed with — believe it or not — shaken baby syndrome."

The social worker, Kimberly Grey, responded: "We are very concerned about where [you] would have gotten this information… because of the sensitivity of the case."

"This whole thing was a medical condition and an accident. And we just want them to admit their mistake," Paul Bayne told CBC News on Thursday.

"We can't do anything for our baby right now, and she really, really needs us," Zabeth Bayne said.

The couple have said their daughter's head was accidentally injured by their second son tripping and landing over her body. The couple have been fighting to get back their children ever since.

Supporters of the Baynes continued their weekly protest Thursday morning at B.C. Premier Gordon Campbell's constituency office in Vancouver.

The couple, who now work as night janitors, have begun a legal challenge against the ministry's decision. But they said they likely won't get their day in court until sometime next year because of delays and backlogs in the court system.