(RNS) The nation's Orthodox Jews asked President Bush to allow federally funded research on embryonic stem cells, becoming the third and last major Jewish group to support the controversial research. In a letter to Bush, the Union of Orthodox Jewish Congregations of America and the Rabbinical Council of America said stem cell research should be allowed "under carefully crafted and well-monitored guidelines." "If embryonic stem cell research can help us preserve and heal humans with greater success, and does not require or encourage the destruction of life in the process, it ought to be pursued," the letter said. Both the Reform movement and the Conservative movement of Judaism, as well as the American Jewish Congress, also strongly support the research. Scientists want to take stem cells -- the basic building block of all human tissue -- and search for cures for a number of debilitating diseases. The procedure is controversial because it involves destroying a human embryo in order to harvest the stem cells. Religious groups are split on the issue. The nation's Catholic bishops are lobbying hard to oppose federally funded research, and several anti-abortion groups say the research is immoral. Other groups, however, say the promise for cures to diseases is too bright to ignore. The letter said frozen embryos originally intended for pregnancy should be used for research if they "would otherwise be discarded." But for Orthodox Jews it is still murky whether other embryos should qualify for research, said Nathan Diament, director of public policy for Orthodox congregations. Diament said he was unsure, for example, if people should be allowed to donate sperm and eggs solely to create embryos that will later be destroyed as some have done. "That will certainly require more detailed guidelines and oversight," Diament said in an interview. The letter urged Bush to increase funding for research on stem cells taken from adults, which has far broader support. They also said couples with unused embryos at fertility clinics need a "rigorous informed consent process" before the embryos are used for science, and that Bush should establish a federal oversight body to conduct periodic reviews.