how old are the plants in question? The reason I ask is cause a plant can be sexed before 12/12 if it is old enough. At around 45 days, the plant will start to show its sex. It will be subtle but with a trained eye you will see the males and females. GL[/QUOTE
the time required to show sex in veg varies, i have master kush right now 3 weeks from seed and all them have pre flowers.