“Rubio is not eligible,” Farah told Fox News host Sean Hannity. “He’ll lose 10 percent of the Republican vote because he is not a natural-born citizen. We’ve been through this with Obama now for four years.”

Rubio was born in Miami in 1971. Farah’s argument against Rubio’s “natural born” status relies on a strict definition also used by Farah and others who raised doubts over Obama’s eligibility. The strict definition requires that both parents be legal citizens at the time of the birth.

Rubio’s parents became naturalized citizens in 1975, but were permanent legal residents of the United States when Rubio was born, according to Rubio’s office. Rubio’s official biography has already been scrutinized, due to questions over the date his parents arrived in the United States as Cuban exiles.

Farah’s website, World Net Daily, is now reporting on the potential controversy under the category “Certifigate.” The website first raised the question in May, but Farah raising the issue in a national television appearance could be a signal of things to come should Rubio appear on the Republican presidential ticket later this year.

“You want to open that can of worms again?” Farah warned.

Last April, Obama released his own long-form birth certificate, which proved his birth in Hawaii, in an effort to silence persistent accusations that he wasn’t born in the United States.

Rubio, who is popular with both conservatives and Hispanic voters, continues to come up as the most likely possibility for the vice presidential slot, and each of the front-runners for the GOP nomination have consistently raised his name as part of their prospective “short list” for vice presidential candidates. Rubio has said he does not expect to be asked to join the ticket, but also maintains he will do anything he can to support the nominee.