Democratic vice-presidential candidate Tim Kaine at a campaign rally last week at the University of Michigan in Ann Arbor. (Paul Sancya/Associated Press)

As part of an appeal to millennials, Tim Kaine, the Democratic vice-presidential nominee, shared this tidbit about his three children on Monday: One of them supported Bernie Sanders over Hillary Clinton during the party’s primary season.

Kaine’s disclosure came during a well-attended rally at Iowa State University in Ames, where Kaine — Clinton’s running mate for the past two months — urged young voters to rally around the Democratic ticket in November.

“Hey, we’re a big family on the Democratic side,” Kaine, a senator from Virginia, told his audience.

Sanders, the now-75-year-old senator from Vermont, was a big hit among the millennial generation, consistently outperforming Clinton in Democratic primaries and caucuses among those under age 30. Kaine’s three children are in their 20s.

Though Clinton is far more popular among young voters than Republican nominee Donald Trump, many of them eye her warily. A recent Washington Post-ABC poll found that a quarter of voters under age 40 are inclined to vote for a third-party candidate in November.

On Monday, Clinton delivered a speech in Philadelphia during which she pledged to offer millennials “something to vote for, not just against.”

During his remarks in Iowa — a battleground state this fall — Kaine said he sees millennials as “altruistic and patriotic and thinking globally.”

“I see this in my own three kids, and I see this in you,” Kaine said.

Sanders has also been back on the campaign trail in recent days, urging young voters to support Clinton.