The two little girls have been living with Jennifer and her husband for nine months, forming what she describes as a loving, happy family. 

"They are our children, in our hearts and in our home," said Jennifer. 

The girls were just one step away from officially becoming their children in the eyes of the law, when the couple learned their adoption is now on hold indefinitely — like hundreds of others in Ontario. 

"When we were told, my heart sank," Jennifer said in a phone interview.

CBC News revealed on Monday that the Ontario government has ordered hundreds of adoption cases to stop moving forward while a judge reviews whether the children should have been taken into the care of children's aid in the first place.

Birth parents asked to contact commission

The review involves 200 to 300 cases where inaccurate drug tests by the Motherisk laboratory at Toronto's Hospital for Sick Children may have influenced the decision to apprehend the children. The program used hair analysis to test for drug and alcohol use, but was declared unreliable and was shut down last April.

Birth parents who believe their children were taken away because of the flawed tests are being asked to contact the provincial commission reviewing the cases.

The families hoping to adopt are being told they have to wait.  

"We feel extremely frustrated," said Jennifer, who asked that her last name not be used to protect the family's privacy. 

"Our adoption has not been easy. We just thought we were finally getting to a special point in our family and in our lives that we could say this is done. Having that last piece is so important to all of us."

Another woman who spoke to CBC News is in the process of adopting a two-year-old boy. 

"He's awesome, he's really developing and changing every day," she said. "He brought something into our lives that we didn't know was missing. Now we're a family, so I can't even imagine not having him here with us." 

'Quite shocking'

The Toronto woman and her partner had jumped through all the hoops, passed through the six-month probationary period, and were expecting a court date in March to receive final approval for the adoption. That's now on hold. 

"It was quite shocking to find out that we wouldn't be able to have this finalized in the timeframe that it was supposed to be," said the woman. CBC granted her request for anonymity to protect the family's privacy.

When we were told, my heart sank - Jennifer, would-be adoptive mother

She says she has sympathy for the birth parents on the other side of the Motherisk controversy. 

"If their children were taken away solely based on this one test that's awful," she said. "I'm hoping that's not the case, I'm hoping there's a larger picture of why children were taken away from their biological parents."

"I don't want to lose my son." 

The government and Children's Aid Societies say they cannot predict how long it will take before the cases are resolved. 

An independent commission set up by the province found the Motherisk tests fell short of international forensic standards and found the lab often misinterpreted test results.  

The Motherisk lab reported some 9,000 positive drug tests in the decade before it was shut down. The test results were primarily used in child protection cases in Family Court to argue that kids should be taken from their parents and into care of children's aid.