What's in a royal baby name? Tens of thousands of bets

• British bettors think they know the name of Will and Kate%27s royal baby
• List of royal names is limited and tradition will play major role
• %27Alexandra%27 and %27Philip%27 are favorites

Duchess Kate says choosing a name for her royal baby is "very difficult," and no wonder: It won't entirely be up to her and Prince William.

But her fellow Brits are having no problem choosing names, as they place thousands of bets on "Philip" or "Alexandra" based on little more than whispers, guesses and tradition.

It's one of those cultural quirks that divide the British and the Americans (like their supposedly common language): In America, betting is often seen as semi-seedy or outright illegal; in Britain, bookies and betting shops are as unremarkable as ATMs and Starbucks.

So, two years and a day after Will and Kate's spectacular royal wedding and less than three months before their first baby is due to arrive, the British are betting on whether the infant will be a boy or a girl, on the day of the birth and what it will be called, which, in the case of royal babies, is a limited pool of names that everyone knows.

Diana? Maybe. Elizabeth? Definitely. Suri? Never.

"They can't just pick any name," says Arianne Chernock, an assistant professor of history at Boston University who specializes in the British monarchy. "The monarchy is one of the few remaining points of connection to a very long, deep and storied past. (Thus), these names are symbolic. It's similar to naming a pope."

Simon Clare, spokesman for Coral Bookmakers, one of the three majors in the U.K., with 1,800 betting shops and 10,000 workers, says betting on royal babies is almost as old as the monarchy.

"It's always been a tradition to bet on the royal family because it's a mass market that everyone knows," Clare says. "As soon as a royal baby is announced, it's manna from heaven for bookies, and people bet on everything — name, sex, even hair color."

Recently, the betting on the name "Alexandra" grew so feverish that Coral slashed the odds shorter and shorter, to 2-1, and then eventually suspended betting altogether.

Alexandra is one of Queen Elizabeth II's middle names, and it was the name of her great-grandmother, Queen Alexandra, a beautiful Danish princess married to Edward VII in the 19th century and widely admired for her grace, fashion sense and perseverance over deafness.

And Philip? It's the name of the queen's husband, Prince Philip, Duke of Edinburgh, William's beloved grandfather, who turns 92 in June.

When naming a baby who will be third in line to the throne, boy or girl, the namers look to England's 40 monarchs since 1066. Other potential names for the baby, who probably will have at least three, include Elizabeth, Victoria and Mary (all reigning queens), and Henry, Arthur and James (all kings' names). A sentimental favorite: Diana, for William's late mother.

"I'm placing my bet on Diana," says celeb tracker Bonnie Fuller, editor of HollywoodLife.com, who says the British betting obsession is no surprise.

"It's been a long time since a new heir was born, not since William himself (in 1982)," she says. "I feel, if they have a daughter, the name will in some way honor Diana, maybe not her first name but her second."

Will and Kate are emblems of modern young royals but both pay attention to tradition, says Marcia Moody, a British journalist and author of a forthcoming biography of the former Kate Middleton, Kate: A Biography.

"Family names (such as Elizabeth) have been passed down through the generations on both sides," she says. "I think even if Kate and William weren't members of the royal family, they would both have wanted to choose a traditional name anyway, as well as pay respect to their families."

Can the betting on names be a predictor of names? Clare says probably, based on past track records.

So maybe get ready for baby Princess Alexandra.