CANBERRA, Australia - Australia's Senate narrowly voted to end the country's four-year ban on cloning human embryos for stem cell research, ruling Tuesday that the potential for medical breakthroughs outweighed moral doubts.

The decision -- a rare conscience vote in a country where lawmakers are expected to follow the party line -- sets the stage for the ban to be lifted entirely. The measure now goes to Australia's House of Representatives, but lawmakers had expected the Senate to pose the biggest hurdle.

Stem cell cultures are placed under a microscope. Australian senators have signalled in an intial vote that a ban on the use of cloned human embryos for stem cell research is likely to be overturned. [AFP]

The Senate voted 34 to 32 to allow therapeutic cloning, which involves removing the nucleus of an unfertilized human egg and adding DNA to make it grow in a lab dish.

Scientists had been lobbying for lawmakers to relax rules on stem cell research and allow therapeutic cloning of embryos for medical research. Since Parliament passed Australia's first laws on stem cell research in 2002, scientists have only been allowed to extract stem cells from spare embryos created for in vitro fertilization.

Sen. Natasha Stott-Despoja, a member of the opposition Australian Democrats, praised the vote. "We have done the right thing and created the opportunity for great research to be undertaken," she said.

Opponents warned that the technology could be abused and lead to human cloning and the creation of animal-human hybrids.

Sen. Grant Chapman, from the ruling Liberal Party, likened research that would be allowed under the new legislation to human experiments conducted by Nazi Germany.

"Experiments which subject the zygote, or embryo, to any significant risk are the ethical equivalent of the infamous medical experiments that we're inflicted on the unwilling and uninformed victims in Nazi death camps," Chapman said.

Scientists hope stem cell research will eventually lead to treatments or cures for diseases like Parkinson's and Alzheimer's, as well as spinal cord injuries, diabetes and arthritis.

The potential scientific benefits and the U.S. debate about stem cell research ahead of midterm elections caught Australian media attention last month when Rush Limbaugh, the conservative commentator, accused Michael J. Fox of faking the severity of his Parkinson's disease in a campaign ad for Democrat candidates who support the research. Fox said he was neither acting nor off his medications.

President Bush and others have argued that the promise of stem cells should not be realized at the expense of human life, even in its most nascent stages. In 2001, Bush pledged to limit federally funded embryonic research to the stem cell lines that had been created by the time and in August he vetoed a bill that could have multiplied the federal money going into embryonic stem cell research.

In Australia, Liberal Sen. Alan Ferguson spoke about his daughter's multiple sclerosis diagnosis 13 years ago, and said therapeutic cloning would give hope to people like her.

"I would never forgive myself if I voted against this bill and did not give medical research that extra possible opportunity to succeed in finding a cure for some of those terrible diseases which are now incurable and which afflict so many of our population," Ferguson said.

Fellow Liberal Sen. Guy Barnett said he would vote against the bill despite suffering type-1 diabetes -- one of the diseases that researchers hope to cure with the technology.

"The promises of cures are false and flimsy hope," Barnett said.

Prime Minister John Howard was part of a Cabinet decision in June that the law should not be changed, but he agreed to allow a rare conscience vote on the issue -- instead of requiring lawmakers to follow the party line -- after government lawmakers threatened to revolt.

Australian Cabinet members, including the prime minister, hold seats in Parliament.

Howard, an ally of Bush who sent 2,000 Australian troops to the Iraq war, said Monday that he was undecided how he would vote when the issue came before the House of Representatives, where he holds a seat.

"On one hand, I want to do everything possible to help relieve suffering and to leave open the hope of cures of terrible, debilitating illnesses," he said. "On the other hand, I do have concerns that this may in some areas be a step too far and I am still weighing the matter."