Hillary Clinton clashed with NPR's Terry Gross in a Fresh Air interview aired Thursday over the former senator from New York's evolution on gay marriage.

Gross doggedly chased down Clinton for an explanation on how she came to support marriage equality and whether she had all along or had changed her position.

“[W]ould you say your view evolved since the 90s or that the American public evolved, allowing you to state your real view?” Gross asked.

“I think I'm an American, I think that we have all evolved, and it's one of the fastest, most sweeping transformations that I'm aware of,” Clinton replied.

“I'm pretty sure you didn't answer my question about whether you evolved or it was the American public that changed ...”

“Because I said I'm an American, so, of course, we all evolved and I think that's a fair conclusion ...”

“So, you're saying your opinion on gay marriage changed?”

“You know, somebody is always first, Terry,” Clinton answered. “Somebody is always out front and thank goodness they are. But that doesn't mean that those who join later, in being publicly supportive or even privately accepting that there needs to be change, are any less committed. You could not be having the sweep of marriage equality across the country if nobody changed their mind and thank goodness so many of us have.”

When Gross pressed a bit more - “So, that's one for you changed your mind?” – Clinton accused Gross of “playing with my words.”

“I'm just trying to clarify. So I can understand.”

“No,” Clinton snapped back, “I don't think you are trying to clarify. I think you are trying to say that I used to be opposed and now I am in favor and I did it for political reasons. And that's just flat wrong. So, let me just state what I feel like I think you are implying and repudiate it. I have a strong record. I have a great commitment to this issue and I am proud of what I've done and the progress we're making.”

“I did not grow up even imagining gay marriage and I don't think you did either. This was an incredible new and important idea that people on the front lines of the gay rights movement began to talk about and slowly, but surely, convinced others about the rightness of that position. When I was ready to say what I said, I said it.”

Last year, after she left the Obama administration, Clinton recorded a 6-minute video for the Human Rights Campaign (HRC) in which she said, “I support marriage for lesbian and gay couples.”

In 2011, Clinton told gay glossy The Advocate that she remained opposed to marriage equality.