By Caroline Ryan BBC News Online health staff

Parents are expected to act 'in their child's best interests'

But they can find themselves fighting doctors in the courts if medics feel they are not acting in their child's best interests.

Two mothers have lost their bid to overturn a High Court ruling that their daughters should be given vaccinations, including the MMR jab.

Their former partners had argued their daughters should be vaccinated.

But this is only the latest case where parents have tried to control the medical care their children receive.

Experts say such conflicts are on the increase as the traditional view that 'doctor knows best' is eroded, and more parents feel they are entitled to make a stand.

However, contrary to what many may think, parents do not have the legal right to refuse medical care for their children if that decision could mean the child coming to harm.

'At risk'

Bertie Leigh, senior partner for the medical law firm Hempsons, told BBC News Online: "Parents are only entitled to refuse treatment when it's in the best interests of the child.

"They have the right to decide what is done to their child in the child's best interests, but they do not have the right to kill their child."

Doctors have the ultimate decision Dr Michael Wilks, British Medical Association

He said parents often took decisions which put their children at risk, such as not making them wear seat belts when travelling in cars.

But once a child is in hospital, doctors have to intervene to press for treatment if it is "in the child's best interests" - even if that means going to the courts.

Mr Leigh said: "An adult has an unfettered right to refuse treatment.

"But they do not have an unfettered right to refuse treatment on behalf of their child."

Emergencies

However Dr Michael Wilks, head of the BMA's ethic committee, said all other avenues had to have been explored before doctors would consider involving the courts.

"You have to have a situation which is particularly acute.

Gracie Attard, the surviving conjoined twin, whose case hit the headlines around the world

"In emergency situations, doctors can go ahead with treatment against the parents wishes, even without the court intervening."

There have been a number of high-profile cases where doctors have gone to court in order to argue for a child to be treated against its parents' wishes - or to advise them about the right way to proceed.

Some cases involve religious beliefs, such as where Jehovah's Witnesses object to blood transfusions.

Legal worries

The first case where doctors went to court to press for treatment arose in 1991 when parents argued their Down's Syndrome child should not have a bowel operation.

But the court backed the medical team who felt the operation would improve the child's quality of life.

Since then there have been several high-profile cases, including that of the Maltese conjoined twins Rosie and Gracie, who shared a heart.

In that case, it was clear Gracie would benefit from the operation to separate her from her sister because her heart was keeping both girls alive, and it could not bear the strain.

People are less and less likely to be deferential to science Bertie Leigh, Hempsons

But the operation would result in certain death for Rosie.

Their parents had argued against the procedure, saying doctors were "playing God".

Bertie Leigh represented doctors from St Mary's Hospital, Manchester, who were caring for the twins.

He said there were fears they could be prosecuted for murdering Rosie if the operation took place.

"The doctors in this case knew what they could do, but not if it was lawful or in the children's best interests," said Mr Leigh.

Informed consent

Dr Wilks said his personal feeling was that the court had got the judgment wrong.

"I think the parents should have been entitled to have their decision respected.

"I think the case demonstrated the courts going a step too far in the sense of their involvement overturning the autonomous wishes of the parents."

One of the key issues in these kinds of cases is whether or not parents have been able to make an "informed" decision.

Dr Wilks said: "Informed consent is very, very important.

"But the doctors have the ultimate decision - they have to decide if parents are being unreasonable in their refusal.

"But I suspect in the case of the conjoined twins, the parents were fully informed."

Mr Leigh said: "If the parents refuse treatment, it doesn't matter how well informed they are if doctors feel it is in the child's best interests for the procedure to go ahead.