WASHINGTON - One of Minnesota's toughest congressional races became deeply personal Thursday, with Republican freshman Rep. Chip Cravaack disclosing that his son's autism played a central part in the controversial decision of his wife and two young sons to move to New Hampshire to be closer to her job.

Cravaack and DFL challenger Rick Nolan have been sparring in recent days over two television ads that claim Cravaack no longer lives in Minnesota. Cravaack, who maintains a home in North Branch, says Nolan's claim is a blatant lie.

A DFL ad saying that Cravaack "doesn't even live in Minnesota any more" was pulled from at least one Duluth television station at the Cravaack campaign's request. Another ad remains on the air in which Nolan says that Cravaack is "not from here and he doesn't live here any more."

Cravaack, down in the polls in a DFL-leaning district in northern Minnesota, has been demanding that Nolan pull the ad, but Nolan's campaign has refused, noting that Cravaack criticized former U.S. Rep. Jim Oberstar's D.C.-area residence when he ran against him in 2010.

Injecting autism into the debate has heightened sensitivities in a dispute that was already personal for the 52-year-old former airline pilot and his wife, Traci, whose job as an executive at the Danish pharmaceutical company Novo Nordisk frequently takes her to Boston.

While intended to blunt the DFLers' attacks, Cravaack's disclosure also brings renewed attention to a difficult living situation that was cited as a concern by 42 percent of district residents in a recent poll commissioned by the Star Tribune.

Cravaack has talked before about the 2011 incident in which his older son Nick, then 10, banged his head on a swing at their previous home in Lindstrom and suffered a seizure. Nick and his younger brother Grant, then 7, were being watched by a baby sitter while Cravaack was holding a town hall meeting in Cambridge. His wife was in Boston.

"What happened was a nightmare of any working adult parents," Cravaack said in an interview Thursday. "That you can't get to your child quick enough when they need you most."

Cravaack cited the episode as a catalyst in the family's decision to buy a house in New Hampshire, where his wife could more easily care for their children during Cravaack's trips to Washington. Until this week, the family had sought to keep Nick's special needs out of the public eye.

Cravaack said he has now decided to talk publicly about his son's condition because the DFL is "making my family an issue." A campaign aide described the child's autism as a mild to moderate condition that requires a structured environment. "When Chip was a stay-at-home dad, he spent a lot of time at the local public school with Nick, helping him out," said the aide, Ben Golnik.

Democrats have long questioned the Cravaack family's move, using it to raise doubts about the strength of his community ties. DFLers say they have no desire to delve into Cravaack's personal family matters but do question his ability to represent the district. Nevertheless, the party has decided to offer stations an edited version of their ad without the reference to Cravaack's residency.

"We've made minor revisions and resubmitted our ad, because we stand by our message that Chip Cravaack doesn't understand the issues facing Eighth District families," DFL spokeswoman Kate Monson said.

Nolan said it is Cravaack who has dragged his family into the dispute. "For my opponent to put words into my mouth and accuse me of attacking his family when he made the decision to bring them into the conversation is disappointing," he said.

Cravaack said his situation is no different from that of Nolan, who moved his family to Washington when he served in Congress between 1975 and 1981. Cravaack's campaign cites a Duluth News Tribune investigation of his public and private schedule in 2011 that showed he spent 160 days in the district, far more time than Oberstar did in his final years in office.

"At the end of the day, the issue is not where our family lays their heads down at night," Cravaack said. "The issue is, am I available to my constituents, am I serving the people of the Eighth District?"

As a retired Navy officer and pilot, Cravaack said he is used to the strains of separation from his wife and children.

Kevin Diaz is a correspondent in the Star Tribune Washington Bureau.