Cloning research "clearly upsets the general public" yet it has limited potential for treating disease and adds little to scientific understanding of human biology, according to Professor Austin Smith of the University of Cambridge, local newspaper The Times reported Monday.

    The scientist said that while it is in theory possible that cloned embryonic stem (ES) cells could be used to create patient-matched tissue for treating disease, significant technical barriers mean that this goal may never be realized in practice.

    Research with ordinary stem cells taken from surplus IVF embryos and adult tissue is less controversial and more likely to lead to medical benefits, but has been given much less public attention, he added.

    While some cloning experiments proceed for the sake of intellectual curiosity, the research community should be much clearer about the limitations, Smith said.

    "Its prominence is out of proportion to the significance of what's being done, and there are real question marks about whether it has any utility at all," he was quoted as saying.

    Smith would prefer scientists to focus on understanding ES cells and adult stem cells, both of which will be studied in depth at the Wellcome Trust Center for Stem Cell Research in Cambridge, officially opening on Monday, and of which he is the first director, the report said.

    Smith was also critical of efforts to devise new ways of collecting ES cells without destroying human embryos, which some scientists have promoted as "more ethical" sources of the tissue, the report said.