TORONTO -- A judge has ordered Ontario's chief medical officer of health to testify in a case relating to the health effects of wind turbines.

A southwestern Ontario couple whose family farm sits in a proposed wind farm say they are being blocked in their efforts to determine if the turbines cause any adverse health effects.

Shawn and Tricia Drennan's farm north of Goderich sits in the proposed Kingsbridge II wind farm and one turbine will be about 650 metres from their house.

Shawn Drennan says they heard some people living near an earlier wind farm project sold their properties to the wind farm operator after suffering health problems.

The Drennans say they couldn't talk to those people because they were banned from discussing health issues and are hoping to have non-disclosure clauses in the sale agreements lifted.

Superior Court Justice Mary Sanderson has quashed a lower court ruling and ordered Dr. Arlene King to testify in the Drennan's case.

"We are delighted with the court's ruling," Shawn Drennan said.

"It means those who claim to be in charge of my family's health will be accountable," Drennan said.

Their lawyer Julian Falconer said this kind of litigation "simply feeds an unfortunate perception that someone in government does not want to answer the tough questions."

"I am surprised that the Drennan family should have to go to these lengths to simply be entitled to ask questions relating to legitimate concerns about their health," Falconer said.

Ontario's panel that rules on turbine approvals has ruled that there are "legitimate concerns and uncertainties about the effects of wind turbines on human health," but noted there is a lack of peer-reviewed science on both sides of the debate.

Shawn Drennan said his family has lived on the farm for nearly 90 years and they don't want to leave their community.