Have sex as soon as possible after ovulation. Female sperm live longer and male sperm swim faster. The idea is that the egg having just been releaed will be a girl because all the male sperm have died out.
it's about the stress levels in the father. if he's really stressed or has a high stress job supposedly he is more likely to make girls, and if he's not stressed then it's more likely boys. so maybe pick a fight with him and rape him afterwards??? idk lol.