(CNN) – The same day her rival hammered her in a political ad for her claims to Native American heritage, Elizabeth Warren fired back in an ad of her own, saying Sen. Scott Brown was attacking her family.
"As a kid, I never asked my mom for documentation when she talked about our Native American heritage," Warren says in the spot. "What kid would? But I knew my father's family didn't like that she was part Cherokee and part Delaware, so they had to elope."
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"Let me be clear. I never asked for or never got any benefit because of my heritage," she continues, addressing the central concern that Brown has brought up on the campaign trail and at the candidates' first debate last week. "The people who hired me have all said they didn't even know about it."
"Scott Brown can continue attacking my family, but I'm going to keep fighting for yours," the former Obama administration official concludes.
Earlier Monday, Brown's campaign released a television spot compiling newscasts reporting on Warren's claims, which came in documents from when she was a law professor at Harvard Law School. The spot, designed to cast doubt on Warren's trustworthiness, ends with a reporter asking Warren if there is anything that will "come out about you that we don't already know."
"I don't think so, but who knows," Warren responds.
In May, Warren stirred controversy when she confirmed that she had described herself in faculty directories as having Native American heritage while teaching at Harvard Law School. She said she did so in order to meet others with similar backgrounds.
Opponents quickly seized on her comments, arguing she had tried to use minority status as a way to advance her career. The Crimson , Harvard's student newspaper, printed articles in the late '90s quoting law school administrators hailing Warren's Native American heritage as evidence of faculty diversity.
The New England Historic Genealogical Society provided CNN with initial research showing several members of Warren's maternal family claiming Cherokee heritage. The Native American link extends to Warren's great-great-great grandmother O.C. Sarah Smith, who is said to be described as Cherokee in an 1894 marriage license application. The genealogical society gathered that information through a 2006 family newsletter and said the original application cannot be located.