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...