For Pete Wentz and wife Ashlee Simpson-Wentz, the decision to give their son the middle name of Mowgli came down to a simple bear necessity.

"The Jungle Book was something that me and Ashlee bonded over. It's a cool name," the father of Bronx Mowgli Wentz, born last week, told Ryan Seacrest on his radio Tuesday.

But while the Fall Out Boy bassist, 29, opened about why his son got the name of the rambunctious boy in the Disney cartoon classic, he still refused to reveal the reasoning behind the first name

"We came up with the idea Bronx. We've been throwing [ideas] back and forth a while," he says. "It's kind of cool to just leave the narrative what it is. People are stoked or pissed or whatever. And you're like, you know what: I don't think anyone really has the real story."

Pressed by Seacrest about whether the name, whose initials work out to BMW, was actually a joke, Wentz insisted: "No, no, no, it definitely is his name, but I don't think anybody knows what the real story is of why or how."

The new dad also gushes about Ashlee, 24, saying that she handled the birth better than he did.

"Right before she went into labor, I was like, 'Oh, my god, I think I'm having a heart attack,' " he says. "My heart started beating real fast. You see your wife is in all this pain. And I don't know what's happening right now. She took care of me and made sure I was okay and then went into labor. That's why she's a saint."