Bernie Sanders says sexism, racism, homophobia and ageism continue to impact the political process as US voters determine which presidential campaign to support despite the electorate moving "very significantly in trying to look at candidates based on what they stand for."

Asked in an interview with New Hampshire public radio whether he believes if "gender is still an obstacle for female politicians", the Vermont Senator — who remains the front-runner ahead of that state's primary on 11 February — said yes, noting that "everybody has their own sets of problems" in the eyes of voters taking gender, or age, or sexuality into account.

Mr Sanders said voters are more concerned with a candidate's positions than their gender, age or racial identity.

He said: "I'm 78 years of age. That's a problem. ... If you're looking at [Pete] Buttiegieg, he's a young guy. People will say, 'He's too young to be president.' You look at this one, 'She's a woman.' ... I would just hope, very much, that the American people look at the totality of a candidate, not at their gender, at their sexuality, but at everything."

Mr Sanders' response followed a previous question about whether an "anxiety" exists within the American electorate about choosing a woman president.

Bernie Sanders campaigns with Hillary Clinton Show all 15 1 /15 Bernie Sanders campaigns with Hillary Clinton Bernie Sanders campaigns with Hillary Clinton Democratic presidential candidate Hillary Clinton, followed by Sen. Bernie Sanders, I-Vt. arrives for a rally in Portsmouth, N.H., Tuesday, July 12, 2016. Andrew Harnik/AP Bernie Sanders campaigns with Hillary Clinton A woman holds a sign at an event where Bernie Sanders will appear with Hillary Clinton at Portsmouth High School July 12, 2016 in Portsmouth, New Hampshire. Sanders and Clinton are expected to show unity within the party and a forwarding of their agendas. Darren McCollester/Getty Bernie Sanders campaigns with Hillary Clinton Cerys Coffey, 5, of North Hampton, Massachusetts, walks along a line of supporters waiting to get into a campaign event with Democratic U.S. presidential candidates Hillary Clinton and Senator Bernie Sanders in Portsmouth, New Hampshire, U.S., July 12, 2016. Mary Schwalm/Reuters Bernie Sanders campaigns with Hillary Clinton Democratic U.S. presidential candidate Hillary Clinton and Sen. Bernie Sanders stand together during a campaign rally where Sanders endorsed Clinton in Portsmouth, New Hampshire, U.S., July 12, 2016. Brian Snyder/Reuters Bernie Sanders campaigns with Hillary Clinton Democratic U.S. presidential candidate Hillary Clinton and Sen. Bernie Sanders greet supporters during a campaign rally where Sanders endorsed Clinton in Portsmouth, New Hampshire, U.S., July 12, 2016. Brian Snyder/Reuters Bernie Sanders campaigns with Hillary Clinton Democratic U.S. presidential candidate Hillary Clinton speaks as Senator Bernie Sanders looks on after he endorsed her during a campaign rally in Portsmouth, New Hampshire, U.S., July 12, 2016. Brian Snyder/Reuters Bernie Sanders campaigns with Hillary Clinton Democratic U.S. presidential candidate Hillary Clinton (R) looks on as Senator Bernie Sanders endorses her during a campaign rally in Portsmouth, New Hampshire, U.S., July 12, 2016. Brian Snyder/Reuters Bernie Sanders campaigns with Hillary Clinton Democratic U.S. presidential candidate Hillary Clinton looks on as Senator Bernie Sanders endorses her during a campaign rally in Portsmouth, New Hampshire, U.S., July 12, 2016. Brian Snyder/Reuters Bernie Sanders campaigns with Hillary Clinton Democratic presidential candidate Hillary Clinton, followed by Sen. Bernie Sanders, I-Vt., arrives for a rally in Portsmouth, N.H., Tuesday, July 12, 2016, where Sanders endorsed Clinton for president. Andrew Harnik/AP Bernie Sanders campaigns with Hillary Clinton Sen. Bernie Sanders, I-Vt. waves as he a Democratic presidential candidate Hillary Clinton arrive for a rally in Portsmouth, N.H., Tuesday, July 12, 2016. Andrew Harnik/AP Bernie Sanders campaigns with Hillary Clinton People hold signs outside an event where Bernie Sanders will appear with Hillary Clinton at Portsmouth High School July 12, 2016 in Portsmouth, New Hampshire. Sanders and Clinton are expected to show unity within the party and a forwarding of their agendas. Darren McCollester/Getty Bernie Sanders campaigns with Hillary Clinton Supporters for Democratic presidential candidates Hillary Clinton and Sen. Bernie Sanders, I-Vt. cheer before a rally in Portsmouth, N.H., Tuesday, July 12, 2016, prior to the arrival of Clinton and Sanders. Sanders is poised to offer his long-awaited endorsement of Clinton, hoping to transfer the energy of his supporters into the party's fight against Republican Donald Trump. Andrew Harnik/AP Bernie Sanders campaigns with Hillary Clinton Supporters of Democratic presidential candidate Hillary Clinton sing the national anthem in Portsmouth, N.H., Tuesday, July 12, 2016, prior to a rally with Democratic presidential candidates Hillary Clinton and Sen. Bernie Sanders, I-Vt. Sanders is poised to offer his long-awaited endorsement of Democratic rival Hillary Clinton, hoping to transfer the energy of his supporters into the party's fight against Republican Donald Trump. Andrew Harnik/AP Bernie Sanders campaigns with Hillary Clinton Supporters of Democratic presidential candidate Hillary Clinton sing the national anthem in Portsmouth, N.H., Tuesday, July 12, 2016, prior to a rally with Democratic presidential candidates Hillary Clinton and Sen. Bernie Sanders, I-Vt. Sanders is poised to offer his long-awaited endorsement of Democratic rival Hillary Clinton, hoping to transfer the energy of his supporters into the party's fight against Republican Donald Trump. Andrew Harnik/AP Bernie Sanders campaigns with Hillary Clinton A woman holds poster for Democratic presidential candidate Hillary Clinton during a rally in Portsmouth, N.H., Tuesday, July 12, 2016, where Sen. Bernie Sanders, I-Vt. endorsed her for president. Andrew Harnik/AP

"As a country, we've come a long way", he said, pointing to the election and sweeping re-election of Barack Obama and the Democratic candidacy of Pete Buttiegieg, a married gay man.

Mr Sanders said: "The world has changed, and to those people who think that a woman cannot be elected, you're dead wrong. If you think a gay American can't be elected, you're dead wrong. If you think an African American can't be elected, you're dead wrong."

The interview follows Elizabeth Warren's recent claim that Mr Sanders had told her privately during a 2018 meeting that he didn't believe a woman could be elected president. He has unequivocally denied that claim, saying during last week's debate on CNN that "anybody who knows me knows it's incomprehensible that I would think a woman could not be president".

Asked about his interview comments, Ms Warren said: "I have no further comment on this. ... I have been friends with Bernie for a long time."

Mr Sanders' communications director Mike Sesca responded to criticism of his interview comments, which seized on his use of the word "problem" to reference a person's race, gender or sexuality as a potential obstacle to one's vote, by clarifying that the candidate is "very clearly calling on voters to move beyond the societal scourges of ageism, homophobia, and sexism".