True. And then we come along & manipulate that! LOL! We're only human, when have we been known to keep our fingers out of it? I grow organically. A lot of people wonder why an organic grower would use outside influences to manipulate the sex of a plant. Easy answer. Cannabis is genetically programed to switch sex (just prior to pre flowering) according to environmental influences as a self preservation thing. Since ethylene gas does it, I would think it may be telling the plant, fruit is ripening, so the end of the growing season is here, so lets be mostly female & make as many seeds as possible to continue our species. I use ripening fruit instead of concentrated synthetics, minuite amount, can't over dose. Its worked for me for about 40 yrs. No other obvious effects on plants.