A senior MP has branded as utterly outrageous and irresponsible the attempt by church groups to get MPs to vote against a change in the law that would allow an IVF procedure to stop genetic diseases being passed on to babies.

MPs are facing a flurry of last-minute lobbying before Tuesday’s vote on mitochondrial donation that would allow IVF to use biological material from three “parents”. Most MPs are believed to support the principle of mitochondrial donation, in common with many leading scientists, including the 40 from 14 countries last who week urged the Commons to approve the proposed legal amendment.

However, there are up to 60 opponents of the motion, who take the view of the Church of England and some other campaign groups that parliament is rushing too quickly towards approving the technology for use. The strongest critics of the technique argue that it is tantamount to creating “three-parent babies”.

“It is utterly outrageous in a free society for the churches to tell parents who are in this painfully difficult position that they cannot undergo procedures like this,” said Andrew Miller, chair of the Commons science committee. “It’s irresponsible of the churches to do that.”

“We need to keep our eyes firmly focused on the pain and suffering of the families that have seen children die at a young age, or are having to make serious decisions in their lives. Their needs must trump everything,” he added.

The intervention of the church has made some supporters of the policy nervous that it will not pass. As a free vote left to the conscience of MPs, the debate is not whipped, and it is taking place at a quiet time for parliament, when many might be campaigning in their constituencies.

Fiona Bruce, a Conservative MP opposing the motion, laid a motion on Monday calling for delay as the House “should not be asked to approve regulations of such ethical significance without a fully informed debate and before the results of the above safety tests are available for consideration”.

At the same time, several supportive groups, including the Association of Medical Research Charities, the Muscular Dystrophy Campaign, the Academy of Medical Sciences, the Medical Research Council, the Royal Society and the Wellcome Trust emailed all MPs urging them to back the motion. “We ask you to support mitochondrial donation, which will give families affected by serious mitochondrial disease a chance of having healthy children,” it said. “These regulations are the culmination of seven years of extensive scrutiny. There have been independent ethical reviews, three separate reviews of the scientific evidence on the technique’s safety by a specially convened independent panel of experts, and an extensive public consultation. Together this has revealed broad support and approval from the public in the UK and scientists from around the world.”

MPs have also been invited to listen to a debate held by the Progress Educational Trust in Westminster on Monday evening, hosted by shadow public health minister Luciana Berger. It will be attended by voices on both sides, including Frances Flinter, professor of clinical genetics at King’s College London, John Harris, professor of bioethics at the University of Manchester, Dr David King, director of Human Genetics Alert, and Philippa Taylor, head of public policy at the Christian Medical Fellowship.

Also on Monday, Dr Peter Saunders, of the Christian Medical Fellowship, released five questions for MPs to consider when thinking about how to vote. He said: “The stance of scientists creates huge pressure for MPs, who risk being labelled ‘ignorant’ or uncaring for objecting. But the question is not nearly as simple as it looks on first appearance. These new regulations are dangerous. No other country has officially legalised the techniques and no one can predict what the consequences for future children will be.”

Vicky Holliday, a suspected carrier of faulty mitochondrial DNA who may benefit from mitochondrial transfer in the future, said that critics of the technology needed to catch up with the scientific evidence. Holliday, 38, from High Wycombe, is the mother of Jessica, a baby girl with a fatal neurological condition believed to be the result of mitochondrial disease. She and her husband, Keith Newell, would like to have a second baby, but do not want to take the chance that it may be afflicted with the same condition. Mitochondrial transfer would enable them to replace any faulty DNA Holliday may pass to a child, and thus have a healthy baby.

Holliday said: “They have been examining this technology now for so many years and so many scientists have come out in favour of it. There are those who say there’s not enough research, but that’s just not true.”

“They need to catch up with what’s been going on in this field.”She said that she hoped MPs would come out in favour of the technique, which would give parents like theirs the chance to have a family free of debilitating mitochondrial disease.

“We really want this to go ahead, for ourselves and to give families like ours a choice.”

Rachel Kean, who is in her mid-20s and has a family history of mitochondrial disease, said misinformation around the issue was rife. “I find it incredibly unethical to oppose the prevention of suffering and disease through misinformation,” she said. “We are not talking about designer babies, we are talking about the prevention and eradication of cruel and devastating diseases, and we have witnessed the impact of those.”

She said she was hopeful MPs would vote in favour: “I am optimistic that those who are informed, reasoned and truly want to help those in the most suffering positions will be in favour of this and because of that it will pass.”

Dr Sarah Wollaston, the Conservative chairman of the health committee and a backer of mitochondrial donation, said she believed the motion would pass easily. “I shall certainly be voting for it. To my mind there are some people who have an ethical position on IVF and I wish they present it as that rather than the bogus safety arguments that keep being put forward.

“I think that some of the tactics that have been used in the debate … should not be employed. My view is that this is such a tiny fragment of DNA – 37 genes out of 22,000. It is not about wanting a child that is more intelligent or beautiful, but allowing families to have a child that will not have their life blighted by a disease preventable by technology.

“I think it will get through. I think those who campaigned very strongly against this have a very loud voice, but I don’t think they represent the majority view here.”

However, Julian Huppert MP, a long-time supporter of the change, said: “It’s clear when we debated this last year that most MPs were in favour. If parliament reflects the public, then it will pass easily. My big worry is that MPs decide not to bother showing their faces, which would be a big disappointment.” He said a number of MPs in favour of the amendment had been trying to make sure that enough turn out for it to pass.