Smokers had better brace themselves for a new concern — future lawsuits by their kids over secondhand smoke, according to Mayor Bloomberg.

“What I would worry about is my kids suing me down the road,” the mayor said on his weekly WOR radio show.

When host John Gambling said he hadn’t thought of that, Bloomberg added that rich parents who smoke probably have the most to worry about.

“I mean, you know, ‘I came down with cancer, Mommy, Daddy,’ particularly if Mommy and Daddy is wealthy. Something to go after,” the mayor said.

Bloomberg was discussing a new report that predicted that smoking could be banned in public places across the country — as in New York City — by 2020.