That is the word from the National Institutes of Health, which is issuing draft guidelines Friday on steps scientists must take.
The guidelines rule out more controversial research - using stem cells taken from embryos created just for science - in favor of a limit with broad congressional support.
The public gets a month to comment on the guidelines before final rules are issued by early July.
Last month President Obama signed an executive order expected to set in motion increased research that supporters believe could uncover cures for serious ailments from diabetes and Parkinson's disease to paralysis.
Mr. Obama said he would allow federal taxpayer dollars to fund significantly broader research on embryonic stem cells because "medical miracles do not happen simply by accident," and promised his administration would make up for the ground lost under his predecessor.
The executive order reversed former President George W. Bush's policy on stem cell research by undoing a 2001 directive banning the use of federal funding for research using stem lines created after that date.
In cutting off federally-funded research, Mr. Bush argued that he was defending human life because days-old human embryos - typically from fertility clinics and already destined for destruction - are destroyed to create the stem cell lines.
Researchers say the newer lines created with private money during the period of the Bush ban are healthier and better suited to creating treatment for diseases.