Republican frontrunner Donald J. Trump has a normal sized penis, he assured voters during the opening moments of Thursday night's debate.

Addressing recent criticism about the small size of his fingers and hands, Trump quipped that fellow Republican contender, Florida Sen. Marco Rubio "hit me on my hands," adding as he held up his hands, "Look at my hands. Are they small?," Trump asked. Rubio, he added, implied that if his hands were small, "then something else must be small. I guarantee you there's no problem," Trump said.

To be clear, Donald Trump concedes that though his hands may be small, his penis is not.

The comments come after Rubio asked about the unusually small size of Trump's hands last week. "I don't understand why his hands are the size of someone who is 5-foot-2," he said. "And you know what they say about men with small hands? You can't trust them."

The controversy over the size of Trump's hands dates back to a 1988 satirical print ad in Spy Magazine for Trump's best-selling book, "The Art of The Deal." The author, according to Spy, was "Short-Fingered Vulgarian Donald J. Trump," a moniker the magazine would call Trump 12 times over the next eight years, Vox notes.

Spy Magazine - vox.com

Trump's fixation on size continued later in the debate, when the candidate repeatedly referred to Rubio as "little Marco" during a tense exchange.

The correlation between hand size and penis size is still unclear. The validity of Trump's claims about his penis, however, could not be independently verified.