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Twins Jenna and Barbara Bush (search) have no doubt about the secret to their father's success: their mother.

And, as devoted to cleanliness and organization as she is, every once in a while first lady Laura Bush (search) lets loose a curse word to get their attention.

"I think if he had never met my mom, there's no way he could have been as successful as he is just because she is so stable and so supportive ... and so giving," Jenna Bush said in an interview aired Monday on ABC's "Good Morning America."

"I mean, she travels and works for him ... but she would never think not to, you know? They just have a pretty unconditional love," Jenna said.

The twins said their mother has told them she had never experienced stress until she brought home two babies and realized she didn't know exactly how to care for them. Their mother is "bizarrely clean," Jenna said. "And organized," Barbara added.

"Sometimes she'll just say something and Barbara and I will be like, 'Mom!' More to Barbara and I," Jenna said. "She, like, loves to every once in a while, like ... every once in a while she'll, like, say a cuss word and Barbara and I will just be totally shocked, and she does it only for shock value because she's so calm."

For years their mother ordered their father to take off his shoes in the house, to the point that their father himself now points out if a towel lies on the floor.

"He always jokes that he would take off his shoes to walk on the carpet because he didn't want to mess up, like, the vacuum lines on the carpet," Barbara said.