Pete Wentz suffered writer's block after his son was born.

The Fall Out Boy rocker - who became a dad for the first time last November when wife Ashlee Simpson-Wentz gave birth to Bronx Mowgli - was amazed by how much parenthood affected his song writing as he is now less selfish.

He explained: "For the first six months after Bronx was born, I couldn't write at all, and then all of a sudden I started writing again. I think it made me look at the world in a different way. We have a very selfish culture, and we all embrace it, and that's what 'I Don't Care' was supposed to be about, and what 'America's Sweethearts' was supposed to be about.

"I hate explaining lyrics because it feel like 'Whatever' but 'I Don't Care' was about looking at a picture of yourself in the mirror, like the ultimate form of narcissism."

The bassist also claimed that despite being an avid user of micro-blogging website Twitter, he still thinks people know very little about him.

He added to MusicRadar: "I think I have as much mystique as a lot of rock stars did back in the day. Ultimately, you have control over how much of your life people really see. People might think you're an open book, but you're just opening the door a little bit and letting people see a little bit of you."