In the case of cannabis, there are differing points of view. It is thought that the embryo that contains the seed is not a simple diploid cell, but rather a triploid cell (XXX, XXY, XYY or YYY) or even a tetraploid cell (XXXX, XXXY, XXYY, XYYY or YYYY). This theory is plausible. However, if genetic circumstances alone influenced the likelihood of having a pure female plant that only has female flowers, the chances of this happening would be minimal, and since cases of hermaphroditism are at the very least quite rare, it would appear that the genetic make-up of the seed cannot be the sole factor involved in determining the sex of marijuana plants. It is for this reason that some cannabis growers place more importance on growing conditions, since it has been seen that under poor conditions there is a predominance of male plants. This theory could well be correct, especially if looked at it from the point of view of nature itself: a plant, just like any other life form, has a single purpose – procreation. The observation that under adverse conditions there is a certain tendency for a higher number of males to be produced may, in my opinion, be due to the fact that under adverse conditions it is unlikely that the offspring (descendants) will be able to reproduce successfully. Since a female can produce a certain number of female flowers, which will give rise to an equal or lower number of seeds, the higher the number of females, the more descendants there will be. However, under extreme conditions, wise Mother Nature steps in and increases the number of male specimens, since although there is more pollen if there are, for example, 100,000 female flowers, there will never be more than 100,000 seeds, and thus the population will regulate the gender of the plants’ descendants, avoiding overpopulation under less than optimal conditions.
From the blog: Gender: What determines it?
This is just 1 example of why I am trying to use environmental controls to make my grow more prevalent to producing females. Jorge Cervantes is where my original concept came from.