The supplements and other things (sweeteners, antihistamines etc) are to sway a person's 'natural' way to a more girl friendly way. I have had 4 sons, so it may be that my chance of conceiving a girl is much less than 50% based on my diet, lifestyle, frequency of intercourse, husband etc. If swaying increased my chances to 50/50 that's actually quite a feat and would be worth trying for me if I was prepared to 'risk' another boy. I'm not, so I'm going high-tech instead.