It all depends on your mates genes and probability of you having a girl. Nothing to do with positions or anything.
Hi, it is often just the 50/50 chance of whether you have a boy or girl. I will say that there does seem to be a correlation with timing ---- those who have sex on the day of ovulation often seem to have boys and those who have sex a few days before ovulation seem to have girl. The theory to this is that male sperm swim faster and will get to a waiting egg sooner but that female sperm linger longer waiting for the egg when you have sex days before ovulation. But no one has been able to accurately plan to have a boy or girl in the history of having babies. good luck
Hate to tell you this, but your guy's sperm will determine what the gender of the baby is. It has nothing to do with any random superstition such as timing or standing on the head or anything like that. You can only get pregnant when you ovulate, which is typically only once per month.