the female plants are artificially stressed untill they produce male flowers late in flowering. this is not to be confused with genetic hermies. things that will make a regular female produce male flowers in late flowering: a product called reverse is said to do the job it's made by some dutch nutrient company, there is a flowering hormone that will do it, these both ruin your buds, for me flushing wrong(?) worked (the ph became really high) this was in hydro DWC. I didn't get any seeds from it because i chopped them right away.