Sean Preston peers from Britney's hospital window

One blog is pulling for Hamlet. The kid, presumably, is pulling for anything but Jailynn.

All baby name bets were off with Tuesday's arrival of Britney Spears' second child--a boy, not a girl.

Spears may or may not have been caught off guard by the baby's gender, but the celebrity-watching world sure was.

Reports leading up to the pop singer's labor day declared she was expecting a daughter to be named Jailynn--a tribute to her father, Jamie, her mother, Lynne, and her sister, Jamie Lynn, and the presumed palatable alternative to JamieLynneJamieLynn.

Fully 75-80 percent of the entries for CelebrityBabyNamesBlog.com's "What Will Britney Spears Name Her New Baby?" contest through Tuesday were fit for girls, editor Neil Street said.

But a 6-pound, 11-ounce boy was welcomed by Spears and her family 2 a.m. Tuesday at Cedars-Sinai Medical Center in Los Angeles.

The 24-year-old entertainer was scheduled to undergo a Cesarean section at Cedars this Saturday, but took an unscheduled trip there after experiencing discomfort Monday evening, a source tells E! Online.

Cornered outside the hospital on Tuesday, husband Kevin Federline, 28, told LifeandStylemag.com, "Mom and baby are doing well, thanks.

"But we're all really tired."

Apparently to prove that it spoke to the right Federline, the site noted the aspiring rapper was wearing "a black T-shirt and baggy black shorts"--in other words, the usual.

Spears' and Federline's newborn is their second child together. Elder son Sean Preston turns one on Thursday.

There was no word yet from the couple's camp as to the newcomer's name.

Among the baby-name contest entries at CelebrityBabyNamesBlog.com, a tongue-in-cheek Street said his favorite was Hamlet Joseph.

"But I don't think she's going to go for it," Street said.

The editor also didn't think Spears would go the way of magician Penn Jillette, father of Moxie Crimefighter and Zolten.

"Being the American icon she is, I trust Britney will go for a good, solid, traditional name," Street said. "So, I don't think we'll be seeing a Rocket or an Ace or a Zolten."

Street's personal preference?

"I think she should name him Barney after her [maternal] grandfather," Street said. "I think that would be great."