not getting into an argument here, but several knowledgable sources, including Mel Frank, Ed Rosenthal, and an article I read from one of the big breeders about 'feminizing' seeds, all stated quite clearly that additional hours of light DO contribute to more males developing ... I am not a scientist, and don't pretend to be one, but I repeat: I have had only TWO males in 41 years of growing quite a few plants ... I'm not that 'gifted' of a grower, in fact, my plants seem to be either female and healthy, or female and dying ... my point is, I always followed the growing books by Frank/Rosenthal, and had great results at 18 hours of vegging light, 12 hours of flowering light ... if 24 hours works for you, hey, go for it ... but, I bet you've seen a LOT more male plants than I have ... :smokin: