A report issued this week by an independent group of U.S. scientists recommends the establishment of uniform standards for human embryonic stem cell research. The group is calling on institutions to follow the guidelines to make sure sensitive research is carried out in an ethical manner.  Some critics think the guidelines don't go far enough.

A patchwork of regulations now governs research on human embryos for the purpose of finding cures for diseases.  Embryos are a rich source of stem cells, which scientists believe can be manipulated to grow into healthy organs.

Though there are no limits on private research on stem cells, under the Bush administration, federal funding for stem cell research is available only to those scientists who agree to work on designated embryos and embryonic cell clusters. 

Many scientists say the available cell lines are inadequate and the federal regulations too restrictive, and they have sought private funding. Researchers complain that they have had to compete for too few dollars.

Cancer researcher Richard Hynes of the Massachusetts Institute of Technology (MIT) says all this has left the public confused about the status of therapeutic stem cell research.

"There's concern by some people that things that are inappropriate or unethical might be being done,? he said.  ?On the other hand, there's concern by other components of the public that not enough is being done; that research is being delayed because of restrictions."

Dr. Hynes is co-chair of a series of guidelines issued by the independent Institute of Medicine. 

To re-assure the public that research is being carried out in an ethical manner, the report recommends first and foremost protecting the privacy of embryo donors.

Under the guidelines, Dr. Hynes says researchers should in no way attempt to influence people to donate their eggs that have been stored at fertilization clinics. 

"There should be no purchase or sale of these donated materials,? he said.  ?The clinics should not be paid for them.  The donors should not be paid for them.  Nobody should be paid for them.  This should not be a commercial activity."

In addition, the authors recommend the creation of oversight committees at every institution where therapeutic stem cell research is carried out.  Under the recommended guidelines, the committees should consider and sign off on each proposal for growing and using embryos for scientific research. 

Embryonic stem cells are usually harvested three to five days after an egg is fertilized, but before it is viable enough to be implanted into a human womb.  Because the embryo is destroyed when the stem cell is extracted, opponents of the research say it is a form of abortion, which is why the administration is reluctant to use public funds to support it.

David Stevens is head of the Christian Medical Association.  Dr. Stevens says the Institute of Medicine's guidelines sidestep the most important issue. 

"But our great concern is you're still destroying human lives,? he said.  ?Just because you put a nice packaging of ethical guidelines around an immoral practice, destroying one human life for the benefit of another, doesn't make it right."

Dr. Stevens believes more emphasis should be placed on research involving adult stem cells from bone marrow. 

But many observers believe human embryonic stem cells are more versatile and hold more immediate promise.

Marcia Imbrescia is a breast cancer survivor who helped draft the Institute of Medicine guidelines.  Ms. Imbrescia's teenage daughter suffers from rheumatoid arthritis, a lifelong autoimmune disease.

"Patients with diseases and with serious injury learn that fairly quickly that research is fairly complicated, that it take time, that it takes money,? she said.  ?I feel confident that these guidelines will help ensure that embryonic stem cell research will be done ethically and responsibly and will be worth the investment."

The Institute of Medicine report was funded by the National Academies of Sciences and the Elison Medical Foundation and the Greenwall Foundation, both non-profit organizations.