Ronald Reagan's (search) death from complications of Alzheimer's disease (search) has not changed President Bush's stand against using embryos for stem cell research, Laura Bush said Wednesday.

Former first lady Nancy Reagan and others believe the use of stem cells from embryos could lead to cures for such illnesses as Parkinson's (search) and Alzheimer's. Bush's executive order in August 2001, however, limited federal research funding for stem cell research to 78 embryonic stem cell lines then in existence.

"We need to balance the interest in science with moral issues," Mrs. Bush said on NBC's "Today" show, adding that there's going to be an increasing number of people suffering from the disease as the baby boom population ages.

Stem cells can be taken from days-old human embryos and then grown in a laboratory into lines or colonies. Embryos are destroyed when the cells are extracted, a process opposed by some people who link it to abortion.

In a letter to the president the day before Reagan died, 58 senators asked Bush to relax federal restrictions. The letter said only 19 of those lines are now available to researchers and those available are contaminated with mouse feeder cells, making their use for humans uncertain.

"We have to be really careful between what we want to do for science and what we should do ethically and the stem cell issue is certainly one of those issues that we need to treat very carefully," Mrs. Bush said on "The Early Show" on CBS.

On ABC's "Good Morning America," Mrs. Bush referred to alternatives to "abusing embryos" in research. "There are stem cell embryos ready that people can use for research, but it's a very delicate line," she said.

Mrs. Bush is with the president in Sea Island, Ga., for an economic summit of the eight largest industrial nations.