A member of the Stormont Health Committee last night revealed that his hild stopped speaking after receiving the controversial MMR vaccine.
The Rev Robert Coulter (UUP, North Antrim) made his comments during questioning of Northern Ireland's Chief Medical Officer, Dr Henrietta Campbell.
"I am the father of an autistic child who had 20 words in his vocabulary when he got the vaccine," he told her.
"Days later he stopped speaking and hasn't spoken since. It was maybe circumstantial but it has left a doubt in our minds as a family."
Dr Campbell insisted there was a huge wealth of evidence that showed the MMR jab did not cause autism.
"Obviously parents of children with autism need to be given information and absolute care and attention," she said.
"I agree with all the societies that support parents with autistic children that we need to find the reason and we need to spend much more money that we have to date," she added.
Mr Coulter said that if the NHS told the public of the work being done to discover the cause of autism, this would go a long way towards accepting the safety of MMR.
The committee was told that rates of take-up of the vaccine in Northern Ireland are currently at 90.4 per cent. This is among the highest in the UK.
It is recommended that rates should be up to 95 per cent to prevent a potentially fatal measles outbreak.
Ms Sue Ramsey (Sinn Féin, West Belfast) said there must be much more information given to the public on MMR and asked was it not up to parents to choose whether to opt for a single measles vaccine.
But Dr Campbell insisted that replacing MMR with a single vaccine would lead to many deaths of children in Northern Ireland.
"If you use the single vaccine, children will die so why would you use public money to allow children to die? Morally it would not be acceptable."
"If I did that, I would expect you to ask me to resign.
"Of course parents have to make their mind up but we are in the business of protecting the whole population and the only way you can do that is with MMR," she added.