Another source insisted that the baby isn’t a boy at all — but a girl.

The rumors gained weight when Federline appeared on a radio show and refused to answer questions about the baby’s name or gender. “Isn’t that strange when you hear that, when you have a child and people tell you the sex is a different one,�? the DJ asked Federline. He replied: “Yeah it’s crazy. Well it’s even crazier when people are telling me my child’s name.�?

Buzz about the baby’s sex grew louder after a report that Spears was photographed buying pink baby clothes at Planet Blue in Malibu — but her bodyguard confiscated the film.

Spears’ rep didn’t respond to requests for comment.

Why all the secrecy? One source compares it to the recent Suri Cruise mystery and says that the baby’s identity will be released in a PR blitz. Says the source: “I’m hearing that they’ll release pics closer to the release date of Kevin’s new CD [Oct. 31].�?

Now TMZ has obtained a copy of the birth certificate for the latest addition to the Spears/Federline family, and now it's official -- it's a boy!

The certificate, filed today at the L.A. County Registrar-Recorder's office, reveals that the boy's name is Jayden James Federline. The certificate is signed by Kevin Federline himself, although a close inspection reveals that the signature is more like printing. Daddy Fed inked his name on September 13, one day after Jayden was born.

Britney Spears is rumored to reveal the baby’s identity in a PR blitz. “I’m hearing that they’ll release pics closer to the release date of Kevin’s new CD [Oct. 31],�? says a Scoop source