Washington ? A stubborn Senate voted Wednesday to ease restrictions on federally funded embryonic stem cell research, ignoring President Bush’s threat of a second veto on legislation designed to lead to new medical treatments.

The 63-34 vote was shy of the margin that would be needed to enact the measure over presidential opposition, despite gains made by supporters in last fall’s elections.

“Not every day do we have the opportunity to vote to heal the sick,” said Claire McCaskill, D-Mo., a senator less than 100 days following a tough 2006 campaign in which the stem cell controversy played a particularly prominent role. “It is a noble cause,” she added.

The House, which passed similar legislation earlier in the year, is expected to adopt the Senate’s version in the next several weeks for Bush’s veto.

The Senate bill, Bush said, “is very similar to legislation I vetoed last year. This bill crosses a moral line that I and many others find troubling. If it advances all the way through Congress to my desk, I will veto it,” the president said in a statement after the vote.

Despite the criticism, the bill’s chief sponsor urged the president to give the bill another look. “I urge him to reconsider this bill and sign it. Unleash America’s scientists,” said Sen. Tom Harkin, D-Iowa.

Capping two days of debate, the Senate also voted 70-28 to pass a separate measure backed by Republicans. It supported research in adult stem cells.

Bush said this legislation builds on “ethically appropriate research” and he urged Congress to pass the measure “so stem cell science can progress, without ethical and cultural conflict.”

The Senate’s action was the latest act in a drama that blends science and politics on an issue that affects millions of disease sufferers and their families.

“It’s extremely frustrating to go through this Kabuki dance a second time with the president,” said Peter Kiernan, head of the Christopher and Dana Reeve Foundation, which funds research.

“The one thing we know is we will outlast him.”

Stem cells are created in the first days after conception. They are typically culled from frozen embryos, which are destroyed in the process. According to the National Institutes of Health Web site, scientists have been able to conduct experiments with embryonic stem cells only since 1998.

The embryonic stem cells have the ability to transform into a “dazzling array of specialized cells,” the Web site says – the property that scientists and others say offers the potential for the development of treatment for diseases as varied as juvenile diabetes, Parkinson’s and Alzheimer’s.