When Congressman Markwayne Mullin's wife first approached him about adopting 2-year-old twin girls, he balked at the idea.

"Basically I just stopped her, and I said 'Babe we just don't have time. I mean, think about it, all the new responsibilities you have, and how much I'm not around any more, and you're wanting to take on two extra girls. We're not talking about one, we're talking about twin baby girls'," he told KRMG in an exclusive interview.

But Christie Mullin played her trump card, he says. She asked him to pray about it.

"What do you do? Do you pray to the Lord that your wife's heart becomes as selfish as mine? God puts things in your life...and you have an obligation. Instead, I prayed that God would change mine, and I just can't express enough -- God changed my heart."

His other children, two sons and a daughter, needed no convincing.

"Even before the adoption was finalized, from day one, these girls were their sisters. They were repeatedly saying over and over again, 'they need a mommy and daddy, they need a mommy and daddy, they need a mommy and daddy,'" he says. "When you see this, and you hear it in your own kids and the passion they have for them... it just breaks you."

And clearly the girls have settled in well.

"They never have to worry about having daddy wrapped around their finger," Mullin added, "because they've got it."