Hillary Clinton’s likability has been an issue since her first presidential race in 2008.

According to recent poll results, Clinton and Republican contender Donald Trump have both reached historic unfavorable ratings, 52 percent and 57 percent unfavorable, respectively. A Washington Post/ABC News poll, finds both at 57 percent disapproval.

A controversial pieceby New York Times columnist David Brooks blames Clinton’s “workaholic” tendencies, citing a lack of hobbies and an overly ambitious professional life. “Except for a few grandma references,” Brooks writes, “she presents herself as a résumé and policy brief.”

But what if there’s another factor— what Trump might call the ‘woman card?’

According to Harvard Historian Nancy Koehn, gender plays a huge role here, one that can’t be overlooked. “As a woman with so much light on her,” Koehn said in a recent interview with Boston Public Radio, “she is subject to an enormous amount of unspoken, unconscious and more direct gender discrimination.”

Nancy Koehn is an historian at the Harvard Business School where she holds the James E. Robison chair of business administration. To hear her full interview, click on the audio link above.