8 Celeb Dads on the Best — and Hardest — Parts of Fatherhood

Having daughter Maven, now 3, after raising three sons "changed me as a man," Morgan tells PEOPLE. But it doesn't mean he'll be lenient. "[We'll] teach her that money doesn’t grow on trees," he says. "You want something from us? You will earn it. She knows that."

"It humbles you," Legend says of becoming a father to Luna, almost 1. "You start to realize you don’t have all the answers."

"I am overworked and underslept, but that all goes away when I get home and hear little feet running toward the door yelling, 'Daddy!' " says Lopez, father to Gia, 6, Dominic, 3. Becoming a dad "made me want to work harder and get focused and do the right things, so the right things could happen for me and my kids."

Becoming a father for the first time (to daughter Simone, now 15) at the height of his wrestling career, “I was always on the road, splitting my time,” he says. But now, with 1-year-old Jasmine in the mix, "It’s been this awesome, interesting, fascinating balance," he says. "I have this amazing, beautiful teenager who teaches me and her amazing, beautiful baby sister."

"They say, 'Acting is reacting,' and I think it’s the same for parenting," says the ABC star, who is dad to Alexa and Zooey, 9. "We encourage [our daughters] to be unique in their own ways."

"When you have a new generation that you’re helping raise, it’s clear that it’s not only our lifetime that we need to be aware of," he says of twins Gideon and Harper, 6, "but theirs and their children’s." Hence his work with with nonprofits like Global Citizen, which tackles civil rights, environmental and health issues, in hopes of leaving his children with a better world.

In raising twins Dolly and Charlie, 8, it's all about manners, the actor tells PEOPLE. "That really goes a long way. Looking people in the eye when you greet them, saying their name, saying 'thank you' and 'please.' I want to make sure they have gratitude."

"My kids are the reason I wake up and work so hard," says Strahan, a father of four. "It’s not to pay for things. It’s to be an example." For that reason, the former football player chose to show twin daughters Isabella and Sophia, 12, his work ethic "in the real world" when retiring from the NFL and turning to TV in 2007.