WASHINGTON – In a move that is likely to be welcomed by members of Maine’s congressional delegation, the White House is expected to announce a compromise this week on the volatile issue of stem cell research, permitting some forms of the controversial medical research.

The Bush administration would allow federally funded studies to proceed, but the studies would not require the destruction of any additional embryos. The administration is considering funding stem-cell research for a specified period of time, perhaps three years, but only allowing researchers to use cells that have already been harvested by private organizations, such as fertility clinics.

Many scientists believe stem cell research has potential for achieving advances against diseases such as cancer, Parkinson’s, heart disease, diabetes and Alzheimer’s. Opponents of the ban, such as the U.S. Conference of Catholic Bishops, argue that federal funding of the research would make the government complicit in embryo destruction and that the advances can be achieved by using stem cells from adults.

The Bush administration faces an unofficial deadline to reach a decision by July 23, when the president is scheduled to meet with Pope John Paul II, who vehemently opposes the practice.

But Maine’s representatives in Washington believe the potential benefits of stem-cell research outweigh the ethical questions.

Sen. Susan Collins has met with senior Bush adviser Karl Rove at the White House, explaining that extending the ban would be “a mistake.”

In a letter to the president, she wrote that “it would be tragic to waste this opportunity to pursue research that can potentially help millions of people in need.”

The Republican Main Street Partnership, a group of 60 moderate GOP officeholders including Collins and Sen. Olympia Snowe, issued a statement on July 2 supporting the research.

“Federal guidelines established by the National Institutes of Health can insure that this research is conducted under strict scientific and ethical standards,” the partnership wrote in a letter to Bush. “Stopping federal support could set promising disease research back by decades. It should continue under sound and ethical standards.”

In March, many House Democrats, including Rep. Tom Allen, wrote a letter to Bush and Secretary of Health and Human Services Tommy Thompson, urging them not to shut any doors on research using stem cells.

Fellow Democratic Rep. John E. Baldacci also supports the research and believes Bush should reinstitute the original National Institute of Health regulations that funded research involving stem cells from embryos.

The controversy goes back several years, when Congress barred the use of federal money for this type of research. Legislators believed that the procedure could encourage abortions, because the resulting human embryo tissue could be a prime source of stem cells.

The Clinton administration concluded that federally funded researchers may not destroy human embryos, but may conduct experiments on stem cells that privately funded researchers retrieve from embryos. Many scientists believe embryonic cells yield better research results than cells derived from adults. After Bush’s inauguration, the White House suspended the policy pending a review of the science and ethics of the issue.

While the Bush administration has been reviewing the issue, several polls have revealed that a majority of the public supports the research. Several prominent Republican abortion foes, including Sen. Orrin Hatch of Utah and former Sen. Connie Mack of Florida, have endorsed the research.

There have been signals of dissention within the Bush administration on this issue for months.