Podcast: How reliable are gender prediction tests?

There are lots of gender / sex prediction tests and theories out there - from the Chinese gender prediction chart, to nub theory, skull theory and more - but how reliable are they?

We caught up with our favourite GP, Dr Philippa Kaye (take a look at Philippa's dedicated website) who shared with us her thoughts on some of the more well known ones.

How reliable are these gender / sex prediction tests?

1. Three lines

This is what female genitals look like on a scan - and the theory goes that if you see these 3 lines you're having girl (though just because you can't see a penis - doesn't mean it's not a boy). This is the test sonographers will use at your 20-week scan and is probably the most reliable of all the tests we'll mention here.

2. Skull theory

This theory says that boys and girls have different skull shapes. But there is no evidence to say this is true - and even while at your hospital scans they'll measure the width of your baby's head, but this is to check he or she is growing and has nothing to do with working out the sex.

• Find out more abut skull theory

3. Nub theory

This one's to do with what can potentially be seen on the 12-week dating scan (though at this point no one's looking for the baby's sex). We've got lots more about it in our dedicated nub theory article here - but, says Dr Philippa, you may not want to waste your time. Accuracy is said be about 50% - only as good as guessing.

4. Baking soda test

This one says that baking soda is an alkali and if you mix it with an acid it will fizz - the theory is that if your urine is acidic and it fizzes it's a boy, if it doesn't - it's a girl. Dr Philippa's verdict? "Save you baking soda to make a cake with." ?

5. Linea Nigra

This is the dark line you get between the pelvis and your belly button. It's said that if it goes above your belly button you're having a boy, and if it only goes up to your belly button it's a girl.

"There's no evidence this works at all," says Dr Philippa - and not everyone gets one anyway.

• More about Linea Nigra

6. Morning sickness

This theory states that really bad morning sickness means you're having a girl. Any evidence for it? None at all, says Dr Philippa - though you might find it does get worse if you're having twins.

7. Sweet versus savoury cravings

The old wives' tale says that a sweet tooth means you're having a girl and savoury cravings mean it's a boy. There's no evidence for this, says Dr Philippa and, for health reasons, she advises if you do find yourself craving too much sugary stuff it's worth seeing your doctor.

8. Chinese prediction chart, pendulum test, pregnancy 'glow'

• The Chinese prediction chart is based on one found in a tomb in Beijing and says your baby's sex is based on when he or she was conceived - find out more about it in our dedicated article
• The pendulum test is when you swing a ring over your bump to predict the sex
• The 'glow' and good skin/hair is said to be a boy, while dull skin and acne

How accurate are they?Just 50% - says Dr Philippa - ie as good as guessing ?

Pics: Getty

Read more

• What happened when Jools Oliver did the pendulum test?
• The pros and cons of finding out your baby's sex before birth
• Can your health affect your baby's gender?