what is hermy or hermie or herm what ever...
When a plant shows both male and female parts it is considered to be a Hermaphrodite. Hermy, Hermie, and Herm are all shorthand for this.
Reproductive parts first appear in the area between a branch and the main stalk, usually around the 12th branch set at 35 to 40 days depending on strain.
Male parts resemble testicles in a way. They are roundish/ovular at first and grow in clusters. Once the male parts are developed they will open up (like a flower) and drop yellow powdery pollen.
Female parts are more tear drop shaped and will appear with two white hairs that emerge from that. These "hairs" are often referred to as pistils when they are in fact stigmas.
Hermaphroditus is inheritable, and most plants contain the gene for the train. Consider plant sex genes to contain XX, xx, and YY, yy. So that an xxXY may appear at first to be female, but then grow male parts later on for no reason. An XXXy might not grow male parts unless stressed. This isn't entirely accurate, but it gives a grower an idea that their might be a recessive male gene in their female plants that can be activated by stress. This is an evolutionary process designed to allow a plant to breed with itself so another generation could have a chance. Annuals do this commonly.
Professional breeders take advantage of this process. They will start hundreds of plants, and induce all kinds of temperature, wind, drought, and light stress to the plants. The few that do not have both male and female parts are known as "True Females." All woman! So they use chemicals on these plants to force her to produce some basically female pollen. This pollen is used on the plant and from that you have a 99% female seed stock which should stay true to the mother plant.