a true and pure female(less than 20% of female population from reg seeds) will never herm, and never produce balls, no matter what. same with a male except a male has to have an extra chromosome(like a polypoloidy) in order to create female organs, but these types of males are even more special than that because if they self seed they can produce both male and female seeds.
I do not believe this is all true.
First of all, cannabis is a dioecious plant, meaning the plants have specific genetic genders, with associated X and Y chromosomes. There is no "pure" female; either a plant is GENETICALLY a male, or it is a female, period.
Like every other dioecious plant, every single cannabis plant (male or female) has the ability to create male ("stamenate") flowers hard-wired into its DNA. This is a necessary survival trait, helping to ensure that in the wild solitary or rare female plants have a chance at reproduction. This ability is almost certainly autosomal and probably CANNOT be bred out of plants, because if you negate their ability to create flowers, they won't be able to reproduce.
If you go collect hemp/cannabis plants from the wild, you'll find some male flowers on every female plant, assuming they're old enough.
What this means is that under the right circumstances ANY cannabis line can "go hermie", and by that I mean a genetically female plant making male flowers.
I believe that every classic sativa "landrace" drug cannabis strain will "go hermie" late in flowering, and/or under stress, and this matters because any sativa-type drug strain ultimately derives from the landrace genetics.
Now, in practice, any quality cultivar of modern cannabis specifically bred for seedless indoor growing, should have had the TENDENCY for female plants to make male flowers selectively bred out over many many generations. These lines are not "hermie-proof" so to speak, but they should be highly "hermie-resistant", meaning that a well-bred drug strain shouldn't go hermie under normal circumstances even if the female plants get old, or even under quite a bit of stress. But even these resistant plants can still "go hermie" if you apply gibberellic acid, which is a plant hormone that affects sexual development, or even potentially under the right combination of stressors. Note that this is not a one gene "on/off" thing. The tendency to go hermie is probably controlled by many genes and many factors, meaning you can't do a simple 1-2 generation selection to eliminate it.
Now here is the rub:
If you use pollen from a female plant forced to create male flowers, that pollen **CANNOT** contain genetic information different than the parent plant. Any genetic tendency this pollen has to impart a "hermie trait" **MUST** be derived from the mother. Of course, if you're breeding, the other parent matters too, but since you are imparting no new genetic information from either the mother or feminized "father", the offspring CANNOT have a different tendency to "go hermie" than contained in each parent.
If both parents are inbred hermie-resistant lines, the offspring will be too. If both parents are hermie-prone, so will be the offspring. If only one parent is hermie-resistant, well, now you have a situation where the offspring might be hermie-resistant, or not, or somewhere in between, but ITS offspring may express a wide variety of traits with respect to hermaphroditism.
If you're starting with a plant that *all by itself* goes hermie (ie it "rodelizes"), then of course you're going to pass that trait on to offspring via feminized pollen you create. If you're phobic of hermies, then you shouldn't use pollen created this way for breeding.
And here is the dirty little secret.
Lots of popular modern drug strains (I'm looking at you, virtually every "Kush" strain from CA) come from lines where the hermie-tendency has not been completely extinguished. So lots of these will create hermies under the right conditions, or be particularly hermie-prone if crossed. Since there is so little ACTUAL breeding done anymore (ie where breeders do selections over 6-8 generations to stabilize lines) and since everyone seems to love these unstabilized hybrid strains, a significant part of what's actually being grown out there isn't hermie-resistant.
If you never stress your plants, and you pull them early, you may never see male flowers. But let them go late, or stress them. . .not so good.
The problem, I think, isn't people breeding with lines from feminized ceeds per se, its that the lines themselves aren't stable, leading in some cases to unpredictable traits (including hermaphroditism) in offspring down the line.