With only weeks to go before her due date, the countdown is officially on for the arrival of Royal Baby No. 3 — and bookmakers are betting it’s a girl.

But before you start envisioning all the cute little matchy-matchy outfits the baby can wear with older sis, Princess Charlotte, 2, how does one actually reach such a conclusion?

Well, according to International Business Times, the odds are based solely on the old wives’ tale that a “high” baby bump means you’re carrying a girl and a “low” baby bump means you’re carrying a boy. And, as evidenced in recent photos, the Duchess of Cambridge is carrying her bump way up high.

Duchess of Cambridge
The Duchess of Cambridge visits the Royal College of Obstetricians and Gynaecologists on Feb. 27, 2018 in London, England. Photo: Karwai Tang/WireImage/Getty Images.

I know what you’re thinking: The odds are 50/50 and no one actually goes by old wives’ tales anymore, right? True, but for the sake of argument, let’s say that the Duchess and Prince William really are having a second daughter — what name will they choose?

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At the moment, the odds are looking good that there will be a Princess Mary in the near future. The Mirror reports that Mary has 4-1 odds, while the equally royal-sounding Victoria and Alice are tied as the runners-up with the odds of 8-1.

The royal couple is known for choosing traditional names for their kids, so all three names sound like perfectly logical contenders — specifically Mary, which has ties to the Queen’s grandmother.

Ladbrokes, an online betting agency, recently changed the odds-on favourite from Alice to Mary with only weeks to go before the highly-anticipated arrival.

“Punters are convinced the Duke and Duchess are expecting another little girl, and obviously it would be a lovely touch to honour Her Majesty’s grandmother, but it will be interesting to see if any boys’ names are backed over the coming weeks before the birth,” Ladbrokes agency rep Jessica Bridge told International Business Times.

Should the old wives’ tale theory not hold up, Arthur and Albert are currently tied for a royal baby boy, with odds at 12-1. These monikers, in particular, are solids bets considering they’re the middle names of Prince William and Prince Harry, respectively.