A group of US scientists has created 17 new embryonic stem cell lines in the laboratory and made them available for other researchers to investigate.
In the US, scientists cannot make new cell lines with government money
Stem cells are "master" cells that can divide into any of the body's tissues and could be used to replace those that have failed in diseased patients.
The move is seen as a sign that US science will push ahead with studies President Bush has tried to limit.
The new lines' production is reported in the New England Journal of Medicine.
They were made by scientists from the Howard Hughes Medical Institute working at Harvard University, Massachusetts, with private funding.
Currently, federal funds are not available for this type of work.
President Bush has told scientists he will not release US taxpayers' money for the production or investigation of new lines because it involves the destruction of human embryos.
Public researchers can only get money for work on existing lines.
The team behind the new lines hopes to use the stem cells to investigate Type 1 diabetes, with a view to developing new therapies for the disease.
"We hope that sharing these cells will quicken the pace of discovery," said Dr Douglas Melton, who led the research.
According to the US National Institutes of Health, about 15 embryonic stem cell lines are available to US researchers carrying out research with government funding.
Some scientists complain that the 15 approved lines are expensive - as much as $5,000 (£2,700) each. The Howard Hughes team claims that researchers who want to use the cell lines will not be charged other than for the shipping costs to their institution.
Dr Melton said the 17 new lines would be widely available, but he confirmed scientists could not use government money to work with them.
"I think that the field needs to be stimulated and this is an excellent way of stimulating the field," said Dr Leonard Zon, president of the International Society for Stem Cell Research.
Many scientists believe that if they can learn how to control the development of embryonic stem cells they will be able to produce a ready supply of transplant tissue to treat patients with degenerative diseases, such as some heart conditions and Parkinson's, or spinal cord injuries.
Other researchers believe stem cells taken from adults also have this potential - but without the ethical problems associated with working on embryos.