US President George W. Bush on Wednesday vetoed again a bill to expand federally funded embryonic stem cell research, according to US media reports.

This is the second time that Bush has used the veto pen for that purpose.

If the bill Bush vetoed would have become law, the White House said it would have compelled taxpayers -- for the first time in US history -- to support "the deliberate destruction of human embryos."

"The president does not believe it's appropriate to put an end to human life for research purposes," White House press secretary Tony Snow told to a news briefing. "That's a line he will not cross."

"This is, certainly not an attempt to muzzle science," Snow said. "It is an attempt, I think, to respect people's conscience on such an issue."

The bill would have lifted rules set by Bush in 2001 making federal funds available only for research on a small number of embryonic stem cell lines which existed at that time.
 
A year ago, Bush used his first veto against a similar bill to expand embryonic stem cell research championed by top scientists and desired by most Americans. He explained that "this bill would support the taking of innocent human life of the hope of finding medical benefits for others."

However, stem cell research advocates say the technique shows promise for the treatment of degenerative diseases such as Alzheimer's and Parkinson's, and for diabetes.

Polls show as much as 66 percent public support for embryonic stem cell research.

To blunt criticism, the White House said on Wednesday that Bush is issuing an executive order directing the Health and Human Services Department to promote research into cells that -- like human embryonic stem cells -- also hold the potential of regenerating into different types of cells that might be used to battle disease.

(Xinhua News Agency June 21, 2007)