The White House’s policy on research with human embryonic stem cells has been put under new pressure by the dismissal of a leading biologist from the President’s Council on Bioethics last week and by the development, announced today, of new stem cell lines by a Harvard researcher.

Dr. Douglas Melton, a biologist at Harvard, reported today in The New England Journal of Medicine that he had developed 17 new human stem cell lines with private money and would make them available to other researchers. But scientists who are supported by government grants — the vast bulk of biomedical researchers — cannot use the cell lines because they were derived after the White House cutoff date.