Mitt Romney's son Matt caused controversy yesterday by making a birther joke that seemed to align the GOP presidential hopeful with the conspiracy theory that Obama wasn't born in the U.S., a gaffe that has already been slammed by the Democratic Party.

Matt Romney has since apologized for the dumb joke, but Obama's campaign staff and the Democratic National Committee picked up the story only hours after it broke, with DNC Vice-Chair R.T. Ryback pushing Romney to publicly condemn his son's statement.

Matt Romney Makes 'Birther' Joke

Speaking at a campaign event in New Hampshire, Mitt Romney's sons were face with a question about their father's tax returns, which have been under some suspicion. Rather than speak about a date for releasing the returns, Matt Romney decided to joke about the situation, a gaffe that would blow up in the hours that followed.

Speaking to senior citizens in New Hampshire, Matt said his father Mitt would publish his tax returns as soon as President Obama releases his grades and birth certificate.

He [Mitt Romney] is certainly not afraid of anything, not hiding anything, Matt Romney, 40, said. But you know, I heard someone suggest the other day that as soon as President Obama releases his grades and birth certificate and sort of a long list of things, then maybe he'd do it.

'That was not my dad saying that.'

Matt's brother Tagg was quick to clarify the comment (That was not my dad saying that, he said), but the damage was done.

President Obama's birth certificate has been a key part of the so-called birther movement, rooted in a conspiracy theory that Obama is not a U.S. citizen and which has been accused of having racist undertones.

To quell rumors that he was born in Kenya, Obama released his birth certificate back in April, offering proof that he was born in Hawaii and is therefore eligible for the presidency.

Matt Romney's ill-chosen statement, however, has reopened the birther floodgates, with opponents slamming the Republican primary candidate's son for reviving a dead issue and pandering to the extreme fringes of the GOP.

Obama Campaign Bites Back

Matt Romney opened a Twitter account yesterday to backtrack from the birther gaffe. I repeated a dumb joke, he tweeted. My bad.

But Romney's son was too slow for the Obama campaign, who leapt on the remark shortly after sites like Patch and Politico posted videos of the joke online.

Obama's campaign manager Jim Messina slammed him for the joke, accusing the younger Mr. Romney of pandering to the dead-ender fringe of extremists. Messina said the attempt to follow the Tea Party line was an indication of how the Romney campaign planned to get its candidate elected.

This is how the Romney campaign thinks it’s going to win the Republican primary, Messina said. We can’t make them rewrite their talking points. But we can drive up the cost of this kind of politics.”

President Obama's official Twitter feed was kinder to Matt Romney, viewing the birther gaffe more as a tired joke than a serious political attack.

Mitt Romney's son thinks President Obama should release his birth certificate, the Twitter post read. Guess he doesn't have one of our mugs?' The post then linked to a mug with a picture of Mr Obama's birth certificate on it.

'He doesn't have the guts.'

If President Obama's campaign team was irked at Matt Romney's statement, however, the Democratic National Committee was furious. In an interview with TPM, R.T. Ryback, the mayor of Minneapolis and the vice-chair of the DNC, tore into the Romneys for their hypocrisy and their poltical baiting.

It’s a bad joke that the Romneys think they can repeat a lie to distract from his failure to be honest about his income,” Ryback said. He accused Mitt Romney of failing to control his son, and for sitting back while others do the dirty work for him.

“Mitt Romney has never had the guts to stand up when one of his surrogates has said something wrong, even his own son,” Rybak asserted. “He doesn’t have the guts to stand up when someone says something that outrageously wrong.”

Although the GOP presidential hopeful has stated several time that he believes Obama was born in the U.S., he has also failed to condemn other Republicans who take the birther route, including its most infamous supporter Donald Trump.

For Ryback, Mitt Romney's failure to speak out against his son's birther joke is just another way of currying favor with the more extreme elements of the Republican Party, one that smacks of double-dealing.

“I think this is another example of Romney, or in this case the Romneys, saying anything they can to try and win a vote because they can’t win by simply saying what they’re for,” Ryback concluded.

Watch Matt Romney Gaffe

Ironically, Mitt Romney was entangled in a brief birth certificate fiasco of his own this fall. The Republican primary candidate was reluctant to release his certificate when journalists questioned that Mitt was his first name. Papers show that his first name is actually Willard.

Below, Watch Matt Romney Make His Infamous Birther Joke: