Whether it's eating certain foods, or when in your ovulation cycle you have sex, there is no shortage of theories on how you can influence whether you have a boy or girl. Whether they work is a different matter...
Quite a lot of us would choose the gender of our baby given the option. Unfortunately there is no strong medical evidence that there is a surefire way to push the odds one way or another.
There are factors that influence gender at the population level but not for individuals – and no one really knows why sex ratios can shift.
But let’s face it, if you are trying out some of those old wives' tales, you have a 50/50 chance of it working.
Can when you have sex affect your baby’s gender?
One of the most common suggestions for conceiving a boy or girl is to time when you have sex.
There is a theory that male sperm swim faster and die off first so to have a girl you would aim for a few days before ovulation so those slower stronger girl swimmers are the ones to fertilise the egg.
Having sex nearer to ovulation should conversely result in a baby boy.
After World War II, when the soldiers returned, there was a higher number of boys born. One possible explanation is that couples relieved to be reunited were having lots of sex, increasing the chance of sperm being around near to ovulation.
‘But the risk is, if you’re timing sex to the day of ovulation you may actually miss that fertile window,’ says Dr Allan Pacey from the University of Sheffield. ‘Most couples are not going to be able to do this to any degree of accuracy.’
Sex position for having a boy or girl
Another of those old wives' tales that does the rounds is sex position. The usual tale is to make love standing up if you want a boy or in the missionary position if you want a girl.
One myth is to have sex standing up if you want a boy
The theory is to do with how close the sperm ends up to the cervix and how long it then has to travel.
If only it was that easy.
There’s no evidence that position during sex has any impact on the gender of a baby, so just go with whichever one you fancy at the time.
What you eat and the sex of your baby
Does what you eat make a difference? There all sorts of theories around diet, including eating salty foods and plenty of meat if you want a boy and taking out the salt and sticking to dairy if you want a girl.
But once again the evidence isn’t strong. Instead, tweak your diet so you’re in prime position to conceive – boy or girl.
Eat more to have a boy
The one bit of good news if you are trying for a boy is that calorific days are good. Jump for joy and tuck into breakfast every day.
An Exeter University study showed that women with the highest calorie intakes - which included eating a regular breakfast - were a little more likely to have a boy.
‘There is a theory that in times of famine, the sex ratio changes - which would fit with this,’ says Dr Pacey. 'But there are lots of factors at work and it is highly unlikely that an individual couple is going to be able to have much of an influence.’
Remember there are lots of plus points to having a boy or girl. The most important thing is to enjoy the surprise!