There are a lot of old wife's tales about conception, some have an element of truth in them, most do not.

Does Having Sex In The Missionary Position Determine Whether You Have A Boy Or Girl?

No. There is no evidence to suggest that, nor are you likely to have a boy if you have sex standing up or when your partner enters from behind. Nor is there any evidence that lying on your back with your legs in the air after sex will improve your chance of conceiving - but if you want to try it make sure you close the curtains!

Are You More Likely To Have A Boy If Your Partner Has Brothers?

No. Your partner's sperm does determine the sex of the baby, but whether you have a boy or girl is a random process. Your eggs contain just a female or X chromosome, whereas a man's sperm contains either a male, or Y, chromosome or an X. The sperm that gets to the egg first and fertilises it will determine the sex of the child. Female sperms are larger and swim slower than the males. So why don't you always have boys? Well, when the male sperm arrives the egg may not have been released from the ovary and the sperm dies off. The female sperm arrives later by which time the egg has been released and fertilisation takes place. If you want a boy try having sex as close as possible to ovulation when the egg is released, or just after if you want a girl. You can buy an ovulation testing kit to help with timing.

If You Already Have Two Boys Or Girls, Are You Likely To Have A Third?

Yes. Although sex selection is random, some men have better quality X or Y chromosomes and have large families of just girls or boys. If you are desperate for a girl, get your partner to go scuba diving! Studies show that the more delicate Y chromosomes don't survive the pressure experienced at depth.

If You Have An Orgasm, Are You More Likely To Conceive A Boy?

No. The male sperm may swim towards the egg a bit faster, but it depends whether the egg has been released when it gets there.

It It Easier To Get Pregnant A Second Time?

Yes. Which is surprising considering you're so tired through looking after the first one! On average it takes couples with children six months to conceive, as opposed to twelve months for couples without kids.

Are Boys More Likely If You Conceive On Odd Days Of The Month?

No. Nor are there fairies at the bottom of your garden!

Can Tight Underpants Harm Sperm Quality?

Yes. Sperm likes to be at slightly below normal body temperature, which is why the testicles are outside the body. Tight pants hold the testicles closely against the body consequently sperm quality can be reduced. Boxer shorts are more comfortable and more sperm-friendly.