Just a quick idea. since plants are really just a guess and check sorta life form (Hey lets mutate some THC buds and see what happened, or lets mutate apples! or tomatoes or flowers or whatever. and if the mutation works lotsa babies get made.)
Well i know for a fact animals like to get fucked up (squirrels with fermented nuts, deer with fermented sugar beets, deer with weed plants) and I'm pretty sure some millions of years ago some animal at that time (be it reptile or mammalian) came along a munched down this plant he found. and whadya know he got all fucked up. 1 this either scared the dog shit out of him and he ran as far away as possible never to return (and shit some seeds out FAR FAR away) or he hung around and just kept spreading seeds locally. either way he ate some bud and shit out some seeds somewhere else. Thats what plants do, the evolve an advantage. cannabis's advantage is the THC and the effect it has on anything that ingests it.
Thats most likely why the male doesn't produce THC, no seeds to poop out if u eat him. he does his job and just adds some more nitro to the soil locally for the next batch. The females grow big ole stinky fruits that will bring in anything that recognizes it from miles away (animal sense of smell, hell a few stoners i know too) have you ever smelled a plant before and after its been dusted? the smell changes a lot and it becomes a lot more abrasive i feel, probably more noticeable amongst non impregnated buds. I'm sure you see where I'm going with this.
basically instead of sugar or starch or whatever else most other fruits and vegetables produce cannabis got THC instead. and I'm sure glad