CHICAGO — Senator Obama celebrated Father’s Day by calling on black fathers, who he said are “missing from too many lives and too many homes,” to become active in raising their children.

“They have abandoned their responsibilities, acting like boys instead of men. And the foundations of our families are weaker because of it,” the Democratic presidential candidate said today at a largely black church in his hometown.

Reminding the congregation of his firsthand experience growing up without a father, Mr. Obama said he was lucky to have loving grandparents who helped his mother. He got support, second chances, and scholarships that helped him get an education. Mr. Obama’s father left when he was 2.

“A lot of children don’t get those chances. There is no margin for error in their lives,” said Obama, an Illinois senator.

“I resolved many years ago that it was my obligation to break the cycle — that if I could be anything in life, I would be a good father to my girls,” added Obama, whose daughters, Sasha and Malia, and his wife, Michelle, watched from the audience.

Mr. Obama’s appearance at the Apostolic Church of God was his first address to a church since he ended his membership at Trinity United Church of Christ, where he had worshipped for 20 years, following inflammatory remarks there by his former longtime pastor and others.

Mr. Obama frequently emphasized the importance of God in his life and ended the speech by asking the congregation to “Pray for me. Pray for Michelle.”

Mr. Obama often speaks about the importance of parental involvement. In Washington, he sponsored legislation to get more child support money to children by offering a tax credit for fathers who pay support, more efficient collection, and penalties for fathers who don’t meet their obligations.

The issue adds to his family values credentials and lets voters see him delivering a stern message to black voters.

“We can’t simply write these problems off to past injustices,” Mr. Obama said today. “Those injustices are real. There’s a reason our families are in disrepair … but we can’t keep using that as an excuse.”

Mr. Obama urged black parents to demand the best from themselves and their children.

He compared it to his own presidential campaign and early comments from black voters who said they liked him but didn’t think a black man could ever be elected president. He said they were admitting defeat before the competition had even begun.

“That was when I wasn’t black enough. Now I’m too black,” he said in a joking aside.

He said parents who proudly tell him their child gets great grades, all B’s, should encourage them even more.

“All B’s? Is that the highest grade?” Mr. Obama said. “It’s great that you can get a B, but you can get a better grade. It’s great that you’ve got a job, but you can get a better job.”