When Ethan Hayes, a senior at Howard University, talks to his mother about politics, they don’t always see eye to eye.

During the 2020 presidential campaign, Mr. Hayes was skeptical of Joseph R. Biden Jr. because of his record on criminal justice. His mother, Lindi Hayes, who said she grew up in a “fairly conservative” Christian household, felt differently.

“Well, look at the alternative,” Ms. Hayes would tell her son, warning against four more years of President Donald J. Trump.

“I don’t want to look at the alternative,” Mr. Hayes would reply. “I want to look at someone brand-new.”

The mother-son split mirrors a broader generational divide among Black voters on President Biden, who needs their support as he runs for re-election. Although Black voters were a key constituency that sent Mr. Biden to the White House in 2020, polls show that Black voters under 30 have far less enthusiasm for Mr. Biden than their elders do.

The Democratic National Committee said it has invested in reaching young Black voters through a variety of initiatives, including issuing grants to states to expand voter registration and hiring campus organizers in battleground states.

But Quentin James, a co-founder of the Collective Pac, an organization that aims to elect Black officials, said the generation gap was “going to be a huge challenge for Democrats.”

“I’m very nervous in our ability not only to maintain Black voters but engage younger Black voters in the way we need to to win 2024,” Mr. James said.

The New York Times spoke to students at Howard, the renowned historically Black university, in the days leading up to Mr. Biden’s commencement address there on Saturday. Most of them said they would still vote for Mr. Biden rather than a Republican. They spoke about their views, how their opinions differ from their parents’ — and what they want for the future.

Here’s what some of those young voters think:

“I don’t really see any other contenders right now,” said Mr. Coulibaly, a 20-year-old finance major from Maryland.

Still, he said he was disappointed in the White House’s response to state efforts to restrict abortion rights. He was there when Vice President Kamala Harris spoke about abortion last month in a speech at Howard, her alma mater. He remembers thinking, “This feels nice, but what’s the plan?”

Mr. Coulibaly leans more progressive than his parents. His mother supports abortion rights but does not often speak about the issue, he said. She supports Mr. Biden “a lot more” than he does, Mr. Coulibaly said. But he still plans on voting for the president.

“He’s old and white, and I’m young and Black,” said Ms. Muhammad, a 20-year-old nutritional science major from New Jersey. “It’s just a really big disconnect.”

She plans to vote in 2024 but does not know whom she will vote for yet. Her parents voted for Mr. Biden because they felt he was the best chance to beat Mr. Trump. She expects they will vote for Mr. Biden again.

“I do want more out of him than my parents,” Ms. Muhammad said.

“My biggest stance is on education,” said Mr. Brantley, a 20-year-old political science major from Chicago. “In order to have well-rounded citizens, you have to make sure it’s affordable.”

Mr. Brantley said he appreciates that Mr. Biden helped the economy rebound after the pandemic. He also said he would be watching to see what happened with Mr. Biden’s student loan relief plan, which was being held up in the courts. Although Mr. Brantley supports the plan, he said his father did not believe in “handouts.”

“Unfortunately, my Dad, he does believe I should be one to pay my own student loan debt back,” Mr. Brantley said.

“I feel like whenever voting comes along, it’s always the lesser of two evils,” said Ms. Senat, a biology major from New York. She said she wouldn’t describe herself as “excited” about the presidential campaign.

Her parents support Mr. Biden opening up a legal pathway for Haitian immigrants, but she thinks the president could do more to invest in her parents’ home of Haiti.

“More could be done,” she said.

“It will be great to have someone who’s young,” said Mr. Mensah, a civil engineering major from Minnesota. He plans to vote in his first presidential election in 2024. But he said he was hoping for a candidate closer to his age.

“Not to insult Joe Biden, but I feel like it’s a stress on him,” he said.

He does give Mr. Biden credit for trying to cancel some student loan debt.

“If that’s able to pass through, that’s a huge feat,” Mr. Mensah said. “Taking that off would be great for not only people that have a huge debt but people like me who are coming through.”

Mr. Hayes and his mother agree on most policies. But he said that as of now, he would not vote for Mr. Biden.

He acknowledges that unlike Mr. Trump, the president is not saying “crazy” things on Twitter. But those antics were not a big deal to him.

“That’s whatever,” said Mr. Hayes, a supply-chain management major from Indiana. “That doesn’t affect my life, bro. I just feel like I’m not being helped. He’s taking the vote for granted.”