The Bush administration has revamped the charter of the federal advisory committee that addresses the safety of research volunteers, stating for the first time that embryos in experiments are "human subjects" whose welfare should be considered along with that of fetuses, children and adults.

The addition of human embryos to the committee's charge -- completed at the beginning of October but not yet posted on the federal Web site that lists such committees -- marks the latest effort by the administration to bring the unborn under the umbrella of federal health protections. In September the administration enacted a new policy that extends certain health benefits to fetuses.

The new move does not mandate that embryos used in research be given the same protections as fetuses, children or adults. The committee can only offer recommendations to the Department of Health and Human Services, which would then have to initiate rulemaking or encourage legislation if it wanted to put new protections in place.

But the wording marks a political victory for those in favor of increased protections for the unborn, experts inside and outside the government said. And depending on whom the administration selects to sit on the committee, it could be the start of a process that could result in greater restrictions on embryo research at some fertility clinics, universities and research labs, experts said.

Embryos are the balls of cells that constitute the earliest stages of human development. Fetuses, representing a later stage of development, already have a limited amount of protection under federal research rules, but scientists' attention has increasingly turned to embryos to improve understanding of birth defects and infertility and as a source of embryonic stem cells, which researchers hope to turn into therapies for a variety of degenerative diseases.

Opponents of embryo research hailed the change in wording.

"It's very welcome that HHS is recognizing the need for sound norms on human experimentation across the entire spectrum of life," said Richard M. Doerflinger of the U.S. Conference of Catholic Bishops.

Others noted that just because the committee now has embryos in its purview does not mean the group will ever act on that authority.

Several others, however, called the move an inappropriate political and religious intrusion into a scientific advisory committee that had been charged with improving research protections after several scandals in which patients were harmed in experiments.

Created during the Clinton administration as the National Human Research Protections Advisory Committee, it was allowed to expire in September after HHS officials said they wanted to broaden the committee's charge.

It was reincarnated by the new administration without fanfare Oct. 1 as the Secretary's Advisory Committee on Human Research Protections.

"I'm very concerned that this addition [of the word "embryos"] will serve to seriously politicize the reconstituted committee," said Robert R. Rich, executive associate dean of research at Emory University School of Medicine in Atlanta, who had been a member of the old committee. "Embryos are not included as human research subjects, according to [current federal regulations]. It will be impossible to gain consensus around this issue if appointees to the new committee represent both sides of this very contentious issue, since it is governed by emotions and beliefs and is really not amenable to rational or scientific discourse."

The new charter, a copy of which was obtained by The Washington Post, says "the committee will provide advice relating to the responsible conduct of research involving human subjects with particular emphasis on . . . pregnant women, embryos, and fetuses" and other "populations" of human research subjects.

Arthur J. Lawrence, HHS's deputy assistant secretary for health operations and assistant surgeon general, said he and others who together crafted the charter felt the wording was needed because of the growing inclusion of women in clinical trials. "There's no way you can ignore that some of those women may be pregnant," he said, so it was important to address the possibility that the research might harm the developing fetus.

He said the word "embryos" was included along with "fetuses," because some people use the two words interchangeably.

But experts said the impact of the change was far greater than that, extending the committee's charge beyond pregnant women to include embryos under study in laboratory dishes.

HHS has not named the new committee's members yet. But members of the old committee were previously told by an administration official that the department hopes to include Mildred Jefferson, a medical doctor who helped found the National Right to Life Committee and who three times served as that organization's president.

Marcy Wilder, a former deputy general counsel of HHS and now a partner in the Washington law firm Hogan & Hartson, described the changes as worrisome. "This could be the next step in according embryos new legal rights and the status of the person under the law," Wilder said. "We're seeing the politicization of what should be a scientific advisory committee."

Karen H. Rothenberg, dean of the University of Maryland School of Law and an expert on research ethics, echoed those concerns, saying the introduction of controversy could undermine the volunteerism that makes clinical trials work.

"We can't achieve the promise of clinical research without sustaining and maintaining society's trust," Rothenberg said. "Do we really want to avert our attention once again to embryos and politics and lose the opportunity to finally reach consensus on how to improve the research enterprise?"

Federal funding of embryo-harming research is banned by Congress, but that restriction expires annually unless renewed, and it does not go so far as to define embryos as human subjects.

Stricter rules could force embryo researchers to obtain approval from review boards that currently have the option of ignoring such studies as having more to do with cells than with human beings, experts said. Under one scenario, for example, a medical experiment might be precluded if the research did not promise a direct benefit to the embryo itself.

That could wreak havoc at some fertility clinics. "We do not think that an entity that is designed to protect human subjects of research is the appropriate place to deal with the regulation of reproductive tissues, be they sperm, eggs or embryos," said Sean Tipton, a spokesman for the American Society for Reproductive Medicine.

Others, however, said they were relieved to see the new wording.

"We applaud the administration for explicitly recognizing in the charter that the term 'human subjects' includes all living members of the species Homo sapiens at every stage of their development, and that all deserve protection from unethical experimentation," said Douglas Johnson, legislative director of the National Right to Life Committee.