i heard from a buddi of myne today that if you pop a cuple birth control pills in you soil right when you start your plants that the estrogin makes the plant always a girl
seeds are male or female predominately from seed all cannabis has the potential to become a hermie, they dont just choose sex during veg or flower unless they are feminised seeds.
As for birth control, it works for a growth spurt (tested a few times) but thats it it wont turn a male female anymore than you taking oestrogen will grow you a vagina to go with the boobs.