The physician replied "Down syndrome," stunning the Republican governor who had just completed what many political analysts called a startling first year in office.
She had arrived at the Capitol on an ethics reform platform after defeating the incumbent Republican in the primary and a former two-term Democratic governor in the general election. Her growing reputation as a maverick for bucking her party's establishment and Alaska's powerful oil industry quickly gained her a national reputation.
Now she said she is trying to balance caring for her special needs child and running the nation's largest state.
The doctor's announcement in December, when Palin was four months pregnant, presented her with a possible life- and career-changing development.
"I've never had problems with my other pregnancies, so I was shocked," said Palin, a mother of four other children.
"It took a while to open up the book that the doctor gave me about children with Down syndrome, and a while to log on to the Web site and start reading facts about the situation."
The 44-year-old governor waited a few days before telling her husband Todd, who was out of town, so she could understand what was ahead for them.
Once her husband got the news, he told her: "We shouldn't be asking 'Why us?' We should be saying 'Well, why not us?"'
There was never any doubt the Palins would have the child, and on April 18 she gave birth to Trig Paxon Van Palin.
"We've both been very vocal about being pro life," Palin said. "We understand that every innocent life has wonderful potential."
Down syndrome is caused by the presence of an extra chromosome in the fetus' cells. It's a genetic abnormality that impedes physical, intellectual and language development.
The mother's age is a large factor in the chances of having a Down child. Once a woman turns 40, the chances of having a Down child is 1 out of 100, according to the Eunice Kennedy Shriver National Institute of Child Health and Human Development.
During her first year in office, Palin distanced herself from the old guard, powerful Republicans in the state GOP, even calling on tightlipped, veteran U.S. Sen. Ted Stevens to explain to Alaskans why he was being investigated by federal authorities.
She asked Alaska's congressional delegation to be more selective in seeking earmarks after Alaska's "Bridge to Nowhere" became a national symbol of piggish pork-barrel spending.
She stood up to the powerful oil industry, and with bipartisan support in the statehouse she won a tax increase on oil companies' profits.
She also found time to pose for fashion magazine Vogue while she was pregnant, and she has been mentioned among potential vice presidential running mates for John McCain.
Three days after giving birth, Palin returned to work in her Anchorage office, accompanied by Trig and her husband.
This was not a mother's typical visit to the office to show off the new baby; instead, she was serving notice that a child of special needs will not hinder her professional commitments.
"It's a sign of the times to be able to do this," she said. "I can think of so many male candidates who watched a families grow while they were in office.
"There is no reason to believe a woman can't do it with a growing family. My baby will not be at all or in any sense neglected."
Neither, Palin said, will the state, as she prepares to lead deliberations for a multibillion-dollar natural gas pipeline. That's the economic future of the state, a means of getting North Slope natural gas to consumers throughout North America.
"I will not shirk my duties," she said.
Other politicians have pressed forward with their careers despite jarring personal news.
Democratic presidential candidate John Edwards continued with his campaign despite the return of his wife Elizabeth's breast cancer, though he eventually dropped out.
Another elected official who has a child with Down syndrome said Palin will likely have detractors, but that shouldn't change ambitions for the mother or child.
U.S. Rep. Cathy McMorris Rodgers, R-Wash., has just celebrated the first birthday of her son Cole, her first child, who was born with Down syndrome. She is busy campaigning for a third term, and Cole often travels with her between Washington, D.C., and the Pacific Northwest.
"Cole opened my eyes to the pain and trouble a lot of families endure," Rodgers said. "He's allowed me to see people and circumstance more deeply, and the generosity of people.
"It's in human nature to focus on the negative, on what the person can't do. In our mind, we are focused on what he can do, what he will be able to do and do very well."
It's not unlike how Palin sees her child.
"I'm looking at him right now, and I see perfection," Palin said. "Yeah, he has an extra chromosome. I keep thinking, in our world, what is normal and what is perfect?"