Sen. Elizabeth Warren (D-Mass.) is rejecting a Massachusetts newspaper’s suggestion that she take a DNA test to prove her Native American heritage.

“I know who I am and never used it for anything,” Warren said Sunday in an interview on NBC’s “Meet the Press.” “Never got any benefit from it anywhere.”

The senator, a potential 2020 Democratic presidential contender, has faced public questions over her citation of family stories to claim Cherokee and Delaware Indian heritage since her first bid for office in 2012. President Trump has turned her claim into a racially tinged attack line, frequently referring to her as “Pocahontas” since May 2016, including at a rally Saturday night in western Pennsylvania. Last week, the Berkshire Eagle, a newspaper published in Pittsfield, Mass., called the issue an “Achilles’ heel” for Warren and urged her to “take the spit test” to put it to rest.

On Sunday, Warren stood by family lore as justification for her claim. Her parents, she said, fell in love as teenagers in Oklahoma and eloped because her mother’s Native American heritage made her father’s family “bitterly opposed” to the union. “That’s the story that my brothers and I all learned from our mom and our dad, from our grandparents, from all of our aunts and uncles,” she said. “It’s a part of me, and nobody’s going to take that part of me away.”

Warren also did not explicitly rule out a 2020 presidential bid but said she is focused on reelection to her Senate seat this year and on supporting party-building efforts across the country. “I’m not running for president,” she said, while sidestepping four attempts by “Meet the Press” host Chuck Todd to pin her down on whether she would pledge to serve out another six-year Senate term.

Warren sought to move past questions about her background last month in an address to the National Congress of American Indians. In that speech, she said she understood why “some people think there’s hay to be made” over the issue, because she wasn’t enrolled in a tribe. “I understand that tribal membership is determined by tribes — and only by tribes,” Warren said, adding that she never used her heritage to advance her career.

A directory of law professors listed Warren as a minority from 1986 to 1995, just before she joined Harvard Law School. When the claim emerged as a flash point in her 2012 Senate race, Charles Fried, a Harvard Law School professor who recruited her, said her ethnic status had nothing to do with how she got the job. “That’s totally stupid, ignorant, uninformed and simply wrong,” he told the Associated Press at the time. “I presented her case to the faculty. I did not mention her Native American connection because I did not know about it.”

On Sunday, Warren cited a promise she made to the Native American leaders last month to refocus the issue on challenges facing their communities. “More than half of all native women have been the victims of sexual violence,” she said. “That is the highest of any group anywhere in America. . . . And the United States government does nothing about that. That is just fundamentally wrong.”