And if the child the Duke and Duchess of Cambridge are expecting in mid- to late-April turns out to be a boy, James or Arthur — a middle name for both William and his father — are the betting person's front-runners at the moment.
Royal tradition leaves little room for originality when it comes to naming a baby who will be fourth in line to the throne — there will be nothing to rival Moon Unit Zappa or Apple for the newest little prince or princess. And likely no Samantha or Lance either.
Still, there might be a bit more latitude for the second child of Prince William and Kate, who had their first, very traditionally named baby — George Alexander Louis — in July 2013.
"With Prince George, it was clear that he would receive a name that had been the name of a previous monarch," says Carolyn Harris, a Toronto-based royal historian and blogger.
"For the second royal baby, we'll probably still see a traditional name, but it may not necessarily be the name of a reigning monarch."
Much speculation has surrounded whether Kate is expecting a girl, and Charlotte — the female version of (grandfather) Charles — was a betting favourite for months. But within the past couple of weeks, punters have been putting a lot more money on Alice, a name that appears several times on the Royal Family tree.
Both sides of the family
Queen Victoria thought Alice was "one of the most attractive girl's names," says Harris, and named her second daughter Alice.
That Alice had a granddaughter Alice of Battenberg, who married Prince Andrew of Greece. Their son Philip, born in 1921, went on to marry Princess — now Queen — Elizabeth and will be the next royal baby's great-grandfather.
Alice of Battenberg had a "long and eventful life," says Harris, noting she hid a Jewish family in Greece during the Second World War.
Another Alice on the Royal Family tree had a Canadian connection. Alice of Athlone, one of Queen Victoria's granddaughters, lived in Canada as wife of the Governor General, Alexander Cambridge, the Earl of Athlone, throughout the Second World War.
Alice's father, Prince Leopold, knew Alice Liddell, who inspired Lewis Carroll's Alice in Wonderland, and there is speculation that Leopold named his daughter after Liddell, says Harris.
The Queen also had an aunt named Alice. That Princess Alice was the Duchess of Gloucester, one of the longest-living royals, who died in 2004 at the age of 102.
Opting for Charlotte would offer William and Kate the chance to acknowledge history and family connections on both sides.
"Charlotte would be the feminine version of Charles so it would certainly honour Prince William's father," says Harris. She adds that it is also the middle name of Kate's sister Pippa, with whom she is very close.
The name Charlotte also has what Harris calls a "very sterling royal pedigree," as it links to King George III's consort Queen Charlotte, who had 15 children and was known for her domestic virtues.
Elizabeth is also finding favour with punters right now, and there's no name with a more current or sterling royal reputation.
The current Queen Elizabeth, who turns 89 on April 21, will become the longest-serving monarch in British history in September.
"She's made the name respectable and interesting," says Ninian Mellamphy, a long-time royal watcher and professor emeritus at Western University in London, Ont.
"No one shortens it."
Harris says naming a baby princess after the Queen "would be honouring her decades of service and the pivotal roles she's played in Prince William's life."
What about Diana?
Much speculation has also focused on whether a baby girl would be named after William's mother Diana, the former princess of Wales who died in a car crash in Paris in 1997.
While Diana might turn up as a middle name, Harris thinks it would be "extremely unlikely" as a first name.
"Being Princess Diana the younger would be an enormous amount of pressure on the young princess, and she would be continually compared to her late grandmother."
Royal history does, however, offer up many lesser-known naming possibilities. Queen Victoria, for example, had nine children born from 1840 to 1857, with names ranging from Alice and Alfred to Helena and Leopold.
Mellamphy even ponders the possibility of going back much farther in history, to the unsettled time that saw Matilda make a claim for the throne in 1141.
"If it's a girl, let's hope they use a good old name like Matilda because it's easy on the ear and it is traditional."
Whatever name is chosen, it is unlikely to be one ripped from the lists of most popular baby names.
Though one popular boy's name is Oliver, a name Harris says Diana favoured for William nearly 33 years ago. But history — and the 17th-century echo of Oliver Cromwell — likely nixed that.
"The one period in the past 1,000 years when Britain was not a monarchy was the protectorate under Cromwell, so that would certainly not be considered a suitable royal name," says Harris.
On the girls' side, Amelia is another popular name and has some royal precedent. But William's cousin, Zara Phillips and husband Mike Tindall had a girl named Mia — a nickname for Amelia — in January 2014.
So that relative closeness makes Amelia an unlikely option for William and Kate, Harris suggests.
Liking the old-fashioned names
While royal baby names tend not to top the most popular lists, Janice Biehn, editor of ParentsCanada magazine, says there is a "real trend towards the more solid, old-fashioned names" at the moment.
And some of them echo names that also appear on the Royal Family tree.
William registers at No. 23 on ParentsCanada's list for the top 100 boy names, while Henry, the official moniker of his younger brother, squeaks in at 99. Elizabeth registered No. 35 on the girl list.
"I do think there is still a sense of you can't go wrong with those names," says Biehn.
"There's just this sense that these are names that are going to stand the test of time and might be unusual but they're not going to be too 'out there' and too hard for them to get a job later."
Harris says the members of the Royal Family who have had the greatest influence on Canadian parents choosing names are those who have lived in Canada.
Queen Victoria's son-in-law, the Marquess of Lorne, served as governor general from 1878 to 1883, living with his wife, Princess Louise, at Rideau Hall in Ottawa.
Into the early 20th century, Harris says, Lorne and Louise became popular Canadian baby names.
Canadian tennis superstar Eugenie Bouchard has said her mom named her and her twin sister Beatrice for the similarly named daughters of Prince Andrew and Sarah, the Duchess of York.