Despite warnings from religious leaders and scientists, British lawmakers have voted to allow a version of in-vitro fertilization that uses the DNA of three different people to conceive a baby.

"Since this is uncharted territory and the children born from this technology would have heritable genetic changes, there are also significant unknown risks to future generations," Dr. Paul Knoepfler, an associate professor at the University of California-Davis, told the British newspaper The Telegraph.

He said the move to legalize two procedures could be an "historic mistake" that poses "serious medical risks" to the people conceived in the procedures. These risks could include developmental defects or increased rates of aging and cancer, he warned.

On Tuesday the House of Commons voted 382-128 to approve a bill allowing the embryo-modification techniques.

One focus of the techniques is mitochondrial disease, in which a woman's eggs have faulty mitochondria, which normally convert food into energy that the body can use. Diseased mitochondria can lead to brain damage, muscle wasting, heart failure and blindness, BBC News reports.
The techniques are intended to replace the mother's mitochondria with those from a donor.

The regulations allow two techniques: pronuclear transfer, in which two human embryos are destroyed in the process of creating a modified embryo with donor mitochondria; and an "egg repair" method called maternal spindle transfer in which the mother's genetic material is inserted into a donor egg with good mitochondria, after which the egg is fertilized in vitro.

Ahead of the Feb. 3 vote, the Catholic Bishops of England and Wales said there are "serious ethical objections" to the procedures, noting that one technique involves "the destruction of embryos as part of the process."

"The human embryo is a new human life, and it should be respected and protected from the moment of conception," said Bishop John Sherrington of the bishops' conference Department for Christian Responsibility and Citizenship.

"This is a further step in commodification of the human embryo and a failure to respect new individual human lives," the Bishops of England and Wales said.

The bill now faces a vote in the House of Lords. Member of Parliament Fiona Bruce was among those who voted against the procedure. She cited concerns about the genetic modification of human beings, saying "the implications of this simply cannot be predicted."

"But one thing is for sure, once this alteration has taken place, as someone has said, once the gene is out of the bottle, once these procedures that we're asked to authorize today go ahead, there will be no going back for society."

U.K. Public Health Minister Jane Ellison supported the bill, saying it is "a considered and informed step."

"This is world leading science within a highly respected regulatory regime," she said, according to the BBC. "And for the many families affected, this is light at the end of a very dark tunnel."

The Catholic bishops noted that there have been no clinical trials of the techniques proposed for approval. A clinical trial of the technique could be legally problematic under the European Commission's 2001 directive barring clinical trials of gene therapy that modifies a subject's "germ line," that is, their sex cells which pass on inheritable genetic characteristics.

Dr. Trevor Stammers, Program Director in Bioethics and Medical Law at St. Mary's University, said that even if babies conceived through the technique are born, "they will have to be monitored all their lives, and their children will have to be as well."

"We do not yet know the interaction between the mitochondria and nuclear DNA. To say that it is the same as changing a battery is facile. It's an extremely complex thing," he said, according to The Telegraph.

Rev. Brendan McCarthy, national adviser on medical ethics for the Church of England, said that changing the human germline "represents an ethical watershed" and proposals about the techniques deserve caution and "comprehensive debate and degree of consensus."

In a Jan. 30 statement, he said the Church of England's position is that the law should not be changed without further scientific study and debate about the techniques' efficacy and safety.