Alan Thicke, Tracey Gold and Roseanne Barr are among the celebrities speaking out against Kirk Cameron, who has come under fire for anti-gay comments he made during an appearance Friday on CNN's Piers Morgan Tonight.

The 41-year-old Cameron told host Piers Morgan that being gay is “detrimental, and ultimately destructive” and that he would not be supportive if one of his six sons told him he was gay.

Cameron came to prominence as a child actor, playing Mike Seaver on the ABC sitcom Growing Pains. More recently, he played Caleb Holt in the 2008 film Fireproof.

Alan Thicke, who played Cameron's TV dad on Growing Pains, took to Twitter to respond to Cameron's remarks.

“I'm getting him some new books,” Thicke messaged. “The Old Testament simply can't be expected to explain everything.”

He later added, “I love Kirk but I may have to spank him … 'tho not in a gay way!”

“I am a strong supporter of the #LGBT Community, and I believe in equal rights for all,” Tracey Gold, who played Cameron's sister on the ABC sitcom, tweeted.

Roseanne Barr wasn't quite as diplomatic, messaging to her followers: “Kirk or kurt or whatever Cameron is an accomplice to murder with his hate speech.”

Stephen Baldwin, however, came to Cameron's defense during an appearance on HLN's Showbiz Tonight.