Michael J. Fox laughed off criticism of his appearance in recent political ads in support of embryonic stem cell research, but said his mother was not as amused.

“She was not happy,” Mr. Fox said during an interview on ABC’s “This Week” that aired yesterday.

Mr. Fox, who has Parkinson’s disease, said his mother, Phyllis, was with him when he shot the ads and knew that he “was struggling to stay still. Because I truly wanted to stay still. It’s more comfortable. It’s not comfortable to be moving around.”

Mr. Fox, who supports embryonic stem cell research as a possible cure for Parkinson’s, drew some conservative criticism after a Missouri ad began running during the World Series. It showed Mr. Fox visibly shaking while urging viewers to vote yes for stem-cell research and for a Democratic Senate candidate over the Republican incumbent.

Radio talk-show host Rush Limbaugh criticized him, claiming that Mr. Fox was “either off his medication or acting.” Mr. Limbaugh, who apologized later in his broadcast, called Mr. Fox “really shameless” in his effort to stir up sympathy.

Mr. Fox, 45, who starred on TV’s “Family Ties,” disclosed his condition publicly in 1998.