The sperm is what determines whether your baby is a boy or a girl, by whether it’s an ‘x’ sperm or a ‘y’ sperm. For a girl, you need an x-chromosome sperm to make it to the egg first. These sperm are marathon-runners, rather than sprinters so they need to be in position before the egg is released and will triumph over ’y’ sperm in a long-distance situation.
There are two popular conception methods, which tie in to these theories:
The Shettles method – Named after its 'inventor', Dr Shettles, who believes that female sperm are stronger and live longer, while boy sperm are faster. This method claims a 75% success rate.
The Whelan method – Just to confuse things, Whelan believes that biochemical changes in your body mean boy sperm are 'preferred' earlier in the cycle. The Whelan method suggests having sex four to six days before your basal body temperature usually rises, and to conceive a girl having sex two to three days before you ovulate.
So, to increase the chances of conceiving a girl you should:
Have sex from the end of your period up to a couple of days before ovulation so they’re hanging about ready for the egg to be released.
Adopt a position (such as missionary) that deposits the sperm further away from the cervix, to give those slow-but-steady female sperm a chance.
Foster an acidic environment in your nethers by avoiding orgasm, which makes the vagina more alkaline – an advantage for male sperm. Lots of women have tried ‘douching’ with vinegar or lemon juice to make the area more acidic but remember it’s very easy to upset the delicate pH balance of the vagina so proceed with caution here. Also, you will smell like a chip shop, which is not alluring.
Follow an acidic diet. Acidic foods include cheese, strawberries and cucumber. They actually don’t include citrus food, which becomes alkaline in the body apparently. Go figure.
Eat foods high in calcium and magnesium, such as dairy products and green leafy veg.
What to do to conceive a boy
Male ‘y’ sperm are faster but with less stamina and they like an alkaline environment. To increase your chances of conceiving a boy, you should:
Have sex the day of or day after ovulation, giving the speedy ‘y’ sperm a chance to impress.
Use a position that allows for deeper penetration (such as doggy style).
Orgasm at the same time as, or just before, your partner, if you can manage that, which creates an alkaline environment in the vagina. Douching with a baking soda solution is used to achieve the same effect.
Follow an alkaline diet. Alkaline foods include chocolate, fish, meat, vegetables and pasta.
Eat foods high in potassium and sodium, such as bananas, baked potatoes and nuts.
What it boils down to is that you can pick a method and give it a go, but if you do manage to swing it one way or the other, it will likely be by such a small percentage, it would make little difference. Give it a try if it makes you happy, but definitely don't put any money on it.