The topic of Feminized seeds normally causes a difference of opinion as well as a few mis-truths by those who dislike Feminized seeds.
Statements saying that Feminized seeds are from hermies and will grow hermies are basically wrong and would hardly reflect good business practice from long established breeders in a very cut-throat seed market.
Cannabis plants have a strong compulsion towards survival of the species, and, should the plant encounter conditions that it is "genetically programmed" to recognise as threatening, it may produce flowers of the opposite sex.
Some plants have a high tolerance to stress/threats and others have a much lower tolerance, the ones with the lower stress tolerance are "more likely to go hermie" than those with a high tolerance.
A plant that hermies easily with very little stress will prodce seeds that will grow into plants with the same low stress tolerance. These seeds are not recommended to be grown.
If you have a plant that has survived being mistreated and only produced a couple of male flowers late in flowering, then those seeds are worth keeping. They will grow into female plants that can take a fair amount of stress, and if you don't stress them they will most likely never grow a ball.
Some plants simply won't respond to stress by producing male flowers. These are the plants that you would like to collect pollen from as the pollen should pass on the stress resistant gene.
Self pollination would be best as both "parents" are the same and the stress resistant gene is not diluted.
How to get the pollen?
Plants grown beyond fully ripe flowering often produce male flowers in a "last ditch" attempt at species survival. Pollen taken from such a plant wouldn't tend to produce hermies as the pollen donor didn't succumb to stress but lived to old age.
Growing plants well past their prime to harvest pollen is time (and resource) consuming and not easily controlled.
A more efficient, easily controlled, way is to induce male flowers without subjecting the plant to any stress.
This is where Colloidal Silver is useful.
Using Colloidal Silver on a plant has nothing to do with stressing the plant.
What happens (in terms that I can just about understand) is that the silver molecules bind themselves to copper molecules in the bud sites of the plant.
Copper is used for ethelyne production by the plant which is used for bud production in female plants.
By binding up the copper molecules and making them unavailable, the Colloidal Silver suppresses the ethelyne production and effectively tricks the plant into thinking it is male.
Again, it has nothing to do with stress, and if the plant didn't have a genetic inclination towards being a hermie, then the seeds will not have the hermie trait either.
To use Colloidal Silver you simply spray the selected plant (or bud or branch of a plant) with colloidal silver before putting it under 12/12 lighting. Repeat the application until male flowers appear.
The fact that you can treat a single bud or branch on a plant and ONLY that area will produce male flowers allows you to harvest pollen and keep flowering the parent plant as a female.
Simply remove the affected branch as the male flowers are reaching maturity and stick it in a flower vase while the pollen sacs ripen, that way you control which flowers get pollinated.
I prefer to use clones for treating with CS as they are small and easily quarantined when needed.
Hope that helps