But her and David's friends have apparently said that the couple – who have a posse of boys – are happy to let the sex be a surprise.
If they want to play the guessing game, there are some old wives' tales that can give them a clue without a visit to the doctor's surgery.
Perhaps, the most curious involves tying a ring onto a piece of string and holding it in front of the mother’s belly. Gently swing the ring, if it moves in a circular pattern you are having a boy; from side to side means it's a girl.
The shape and size of the stomach also are supposed to be a giveaway. If Posh's bump is low and to the front, she is probably expecting another footie buddy for Brooklyn and co. If it's high she'll finally have someone to pass all her Hermes handbags onto.
Similarly, they say if your breasts are noticeably bigger in the first weeks of pregnancy, it’s likely to be a he.
However, if you suffer from back problems, changes in skin tone and generally feel less ‘radiant’, you’re expecting a she – they say that the unborn child is ‘stealing’ some of their mother’s beauty during the pregnancy!
The baby’s heart rate is also said to be another good pointer. Under 140 beats a minute would indicate yet more testosterone in the Beckham family, for over 140 a minute, they should prepare for a shot of oestrogene.
Likewise, mothers who can’t resist sweet cravings are likely to be in for sugar and spice and all things nice, while the opposite is true if you're devouring savoury, salty snacks!
Did you know the sex of your baby before it was born? Leave comments below!