Michael J. Fox, who has been a vocal campaigner for embryonic stem-cell research, is saying that he wishes President Bush had taken a more “sure-footed” approach to the controversial issue. The TV star, 40, told Katie Couric on Friday’s “Today” show (he also spoke on “Good Morning America”) that he was gratified the president had spent so much time studying the issue. Bush said on Thursday that he would allow government funding for research only on about 60 existing stem-cell lines worldwide whose embryos have already been destroyed, meaning there is no chance of life emerging from them. But, Fox said, the president’s decision does not go far enough in trying to push ahead with groundbreaking research to treat diseases such as his own. “We do have a little bit of a feeling though that he’s put us on the launch pad and he’s given us clearance for take-off,” said Fox, “but we have real questions about the quality and quantity of fuel he’s given us.” As he spoke on the morning program, Fox showed signs of fatigue and tremors associated with his disease, which Couric acknowledged. She thanked him for appearing, despite the obvious difficulty. “It takes a while for the pills to kick in,” he replied good-naturedly. Other celebrity supporters of stem-cell research include Mary Tyler Moore, 64, who is a diabetic, and spinal chord injury victim Christopher Reeve, 48.