David Cameron confirmed today that he supports some of the most controversial medical innovations contained in the Government’s Fertilisation and Embryology Bill, shortly before the start of a crucial Commons debate.

The Conservative leader said that he backed proposals for the creation of human-animal hybrid embryos for medical research as well as so-called “saviour siblings” selected by parents in order to provide tissue material for seriously ill children.

MPs of all parties have been granted a free vote on measures to permit the ground-breaking techniques when the debate wraps up this evening.

Yesterday, Gordon Brown hailed the new techniques as “an inherently moral endeavour” which could save millions of lives. But the two major party leaders are split on a further provision of the Bill which would make it easier for lesbians to have babies through IVF treatment, as well as over the abortion limit. Both of these issues are to be debated tomorrow.

Mr Brown will vote in favour of the removal of a requirement for IVF clinics to consider a child’s “need for a father” before offering medically-assisted pregnancy, while Mr Cameron believes it should stay.

The Tory leader has also indicated that he would like to see a reduction in the current 24-week limit for abortion, while Mr Brown has said he will vote for the retention of the status quo.

Speaking in Birmingham today, Mr Cameron confirmed that he backs the creation of both “admix embryos” and saviour siblings. He said: “My own approach to this is the law needs updating and the importance of science and research and getting to grips with genetic disease... I want to see the research go forward.”

In the face of resistance from across parties and religious groups, Mr Brown yesterday exhorted MPs to help “ourselves and future generations” by passing the measures in tonight’s free vote.

The Bill would allow scientists to insert the nuclei of human cells into animal eggs, creating hybrid embryos which are allowed to grow for up to 14 days before being destroyed.

Scientists believe that stem cells harvested from these embryos could provide the key to breakthroughs in the treatment of conditions such as Parkinson’s disease, cystic fibrosis or muscular dystrophy. Research is currently being held up by the shortage of human eggs to create stem cells.

But critics of hybrids have branded them “Frankenstein science”, saying it is obscene to combine human and animal genetics. They also question its benefits, insisting other methods are more effective.

Opponents of the Bill also argue that the creation of saviour siblings necessarily involves discarding embryos which do not provide a genetic match with the existing child, effectively giving parents the ability to create “designer babies”.

Mr Brown insisted Britain should not “turn our back” on vital scientific advances. “I have deep respect for those who do not agree with some of the provisions in the Bill because of religious conviction,” he wrote. “But I believe that we owe it to ourselves and future generations to introduce these measures, and in particular, to give our unequivocal backing within the right framework of rules and standards, to stem cell research.”

The Conservative MP Ann Widdecombe today said there was no proof to back claims that admix embryo research would save lives on a huge scale. “There is no evidence at all that it will save millions of lives,” she told GMTV.

“This is what we were told 18 years ago when embryology was first legalised in this country. Eighteen years later, 2.2 million embryos later, there haven’t been any cures and yet there have been lots of cures and advances from adult stem cell research and recently a lot of advances from umbilical cord tissue.

“Why on earth aren’t we going down the lines where there are advances instead of insisting on this?”

But Evan Harris, the Liberal Democrat MP who is a vocal supporter of the Bill, told the programme: “The legislation says that if scientists can show that the best way to make progress in research into treatments and cures of certain diseases is using embryonic means, then under a strictly regulated basis, under a licence, showing it is necessary or desirable, showing you have to use embryos and only 14 days development... then it should be permissible to use human embryos for that research, or indeed animal-human hybrids.”

Meanwhile, campaigners from the Society for the Protection of the Unborn Child gave warning that amendments to the Bill to remove the requirement for two doctors to approve a abortion could mean more foetuses being terminated.

“These amendments will send the message to doctors: ’When you decide a woman should have an abortion, you don’t need to justify your decision or worry about what other doctors will think’,” said John Smeaton, SPUC national director.

“If MPs vote for such amendments they will show they care as little for health and welfare of women as they do for unborn children.”

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