Two of Sen. Larry Craig's children said Tuesday they questioned him explicitly about "what exactly happened in that bathroom" where he was arrested in a sex sting and believe his assertions that he isn't gay.

Michael Craig said they asked their father about the June 11 incident at the Minneapolis-St. Paul airport, which led to the Idaho Republican's resignation last week after it became public, because "we were shocked" at media accounts of the incident, he said.

Craig, 62, pleaded guilty to a reduced charge of disorderly conduct following his arrest. The arresting officer said in his report that the restroom where he encountered Craig is a known location for homosexual activity.

In an interview with ABC's "Good Morning America," Michael Craig said his father was simply "a victim of circumstance" and "in the wrong place at the wrong time."

"We've known him our whole life. He has been so trustworthy to us, so honest to us, that we believe him," Michael Craig said, the first public remarks on the case by any family member.

Larry Craig adopted Michael and his two siblings after marrying their mother, the former Suzanne Scott, in 1983. Craig has worked in the Senate to promote adoption.

Among the questions he and his sister Shae Howell said they asked their father was "what exactly happened in that bathroom," and they tried to "break down definitions of what words mean," including semantic definitions of sex, Michael Craig said.

"Maybe it wasn't sexual intercourse, but were these sexual actions? Were there sexual feelings? All these terrible things that were said in the media, we asked all those tough questions," Michael Craig said. "I don't want to have an answer based on a legality or technicality or semantics of the words. We wanted to know exactly what happened and after speaking to our dad, we know exactly what happened."

He said that it would make no difference to them if Craig was gay, though they "absolutely" believed Craig's assertion that he wasn't. "It would matter to my mom, but gay or straight, that part doesn't matter," Michael Craig said. "It was a matter of an accusation of a lewd, immoral, illegal act."

He said that by pleading guilty, his father "was just trying to resolve a little problem and he thought it was probably something resulting in something fairly minor. I think he knows he screwed up."

Standing next to their father in Boise on Saturday when he announced his resignation was "tough," Michael Craig said, but "we are family and we stay together through good times and bad." Another sibling, Jay Craig, was said to be out of the country and not available.

The family is angry that so many of his father's colleagues on Capitol Hill had failed to support him in the scandal.

They "made their decision and formed their opinion about it without even talking to my dad," said Shae Howell. "So that was a little frustrating and disappointing too."