Behind Sarah Palin's very public persona as the former Republican vice presidential candidate, the self-described "hockey mom" from Wasilla, Alaska, is above all mother of five: Track, 20, who is in the Army and recently returned from Iraq; Bristol, 19, who gave birth to her son, Tripp, last December; Willow, 15; Piper, 8; and Trig, 19 months.
Of all the controversies and challenges that the former governor of Alaska has faced, none has been more personal than her unexpected pregnancy with a baby whom she learned had Down syndrome. In an interview to air on "20/20," Palin opened up to ABC News' Barbara Walters about son Trig and her concerns about the pregnancy.
Palin discovered she was pregnant with a fifth child while attending a conference in New Orleans in 2007. Then Alaska's first female and youngest governor at age 43, she said she was initially hesitant.
"For a fleeting thought, I knew what women go through when they're facing what they believe at the time are less than ideal circumstances," she said. "I never thought, do I want another child? What I did think for that split second was, Gee, now, of all times? And yeah, I'm no spring chicken."
After she returned to Alaska, a test revealed that Palin was carrying a baby with Down syndrome, a genetic condition that affects a child's intellectual and physical development. She said the moment gave her pause.
"I thought, 'God, unless you know more than I do about all this, how in the world would I handle this?'" she told Walters.
Ninety-two percent of women who get that news terminate the pregnancy, according to research reviewed by Dr. Brian Skotko, a pediatric geneticist at Children's Hospital Boston.
Palin said she knew abortion was an option but was able to overcome the fear of the unknown to go ahead with the birth.
"I knew that the option was there. ... I thought again, for that split second, 'OK, now I know, too, why, when that fear strikes you, because of the unknown,'" she said. "I understood then, too, why a woman would consider [abortion] an easier path to perhaps, if you will, do away with the problem, instead of understanding that every child has purpose. There is destiny for every child. And it can be good, in our world. And that's what I held onto."
When asked by Walters if her "right to life" stance on abortion dictated her choice, Palin said her decision was not "politically motivated."
"My decision certainly wasn't a political decision. It was a holding onto a seed of ...that promise that things will be okay if we choose life. And that certainly has come to fruition in my life," she said.
Although she "chose life," Palin said she and husband Todd struggled with how to tell the other children -- especially the two youngest, Piper and Willow, who both joined their mother for portions of the Barbara Walters interview.
"We didn't find out he had Down syndrome till the day he was born," Willow said. "So that was kind of a shock. But we didn't really care. He's still our brother."
When asked why she didn't tell the children earlier, Palin told Walters that she was not emotionally prepared to share the news with her family yet. Instead, she said, she wrote it all down in a letter, which she hadn't yet delivered when Trig was born.