The House has passed legislation in support of stem cell research. The vote was 253 to 174. President Bush’s only use of the veto was to nix a similar bill last year, and this proposed expansion of research is seen as a direct challenge to him.
The stem cell bill was among the top priorities for the Democrats, who took control of Congress last week, but Mr Bush has vowed to veto it.
Advocates of stem cell research say it could lead to cures for diseases such as Alzheimer’s and Parkinson’s.
Mr Bush says the research would destroy human life in the name of science.
The bill was passed by 253 to 174, but fell short of a two-thirds majority needed to overcome the veto.
“Today, by passing legislation to expand stem cell research, the House gave voice to the hopes of more than 100 million Americans and their families,” said House Speaker Nancy Pelosi.