Joe Biden faced criticism after telling a teenage girl’s brothers to “keep the guys away from your sister”.
The former US vice-president, who is leading the race to become the 2020 Democratic nominee, is said to have made the remark while campaigning in Iowa on Wednesday.
Liz Goodwin, a political reporter at the Boston Globe, tweeted: “Joe Biden meets a voter’s granddaughter in an Iowa coffee shop and asks her age.
“She says she’s 13. He addresses her brothers. ‘You’ve got one job here, keep the guys away from your sister.’”
The tweet has since been shared and commented on hundreds of times, with many criticising the Democrat hopeful’s comments.
American activist and writer Amy Siskind tweeted: “This is a disturbing mindset that keeps repeating.”
Twitter user Brian Hurn suggested someone should “tell Joe it’s not the 1950s”, while another wrote: “Where would women be without brothers choosing who they are allowed to date.”
Meanwhile, Mangy Jay wrote: “Oh dear god I wish he would stop.”
Several people jumped to Mr Biden’s defence, however, saying they could not see the harm in his comment.
Twitter user Ginger B Soapbox said “asking a brother to keep a sister safe isn’t that big of a deal,” adding: “We gotta stop it with the candidate purity stuff.”
Chas Krish tweeted: “Am I the only one who thinks most people are overreacting to this comment!? Literally every boy who has a little sister has heard this.”
And Navi Rose said: “I really think it’s a generational thing. He means well. Just doesn’t get it.”
It is not the first time Mr Biden’s comments have faced criticism during his campaign.
On Monday, the 76-year-old triggered a backlash among Democrats after suggesting Republicans would be willing to cooperate with the party once US president Donald Trump is out of office.
According to a Daily Beast reporter, he reportedly said: “With Trump gone you’re going to begin to see things change because these folks know better. They know this isn’t what they’re supposed to be doing.”
Earlier on Wednesday, Mr Biden, whose son died of brain cancer in 2015, also pledged to “cure cancer” if elected as president.
Some polls have put Mr Biden as favourite to oust Mr Trump from the White House, with recent Quinnipiac surveys suggesting the Democrat could beat the president by as much as 13 per cent.