LOS ANGELES, July 18 (Xinhua) -- After a bill favoring embryonic stem cell research passed in the Senate, leaders of the U.S. scientific community Tuesday night urged President George W. Bush to support the act.

The Stem Cell Research Enhancement Act, which will expand federal support for embryonic stem cell research, was approved in the Senate earlier Tuesday by a vote of 63 to 37, four votes short of the two-thirds majority needed to override a presidential veto that Bush had vowed to exercise.

The American Association for the Advancement of Science (AAAS),the largest scientific organization in the United States, called on Bush to reconsider, noting that stem cell research is "an extremely promising approach" to treating diabetes, spinal cord injuries and Parkinson's and Alzheimer's diseases.

"We in the scientific community are hopeful that you will review this measure with an open mind and open heart and then sign it into law," the leaders of the AAAS wrote in a letter to Bush.

By far, human embryos appear to hold "the greatest therapeutic promise" for advancing stem cell research, they said.

Bush had stated clearly that he would not accept utilization of human embryos to derive stem cells despite appeals from prominent Republicans including Nancy Reagan and California Governor Arnold Schwarzenegger.

It was the first time that Bush would veto a legislation passed by the Republican-controlled Congress, and it was the first time "no deal could be cut," White House spokesman Tony Snow said earlier.

"H.R. 810 (the act) would enable the Federal government to exercise a higher level of regulation and ethical oversight over human embryonic stem cell research than it can now," said AAAS Board Chairman Gilbert Omenn and Chief Executive Alan Leshner.

"We see H.R. 810 as an affirmation of life, and of the potential of scientific and medical research to improve the human condition," they said, adding that some 400,000 embryos, left over from in-vitro fertilization techniques, would be discarded otherwise. Enditem