We all know that plants have chromosomes for both male and female, but depending on the environment and amount of stress, one type chromosome will be repressed, so I don't believe sex is determined during conception of a seed. Let me show ya'll the 'favorable environment' theory,
"When conditions are favorable for plants, a higher percentage of females are formed in order to ensure a population boom in that growing are. Fewer males are formed since less pollen is needed to maintain a high survival rate. When conditions are harsh, more males are formed, since more pollen is needed to ensure the current female population is fertilized. Also, more pollen can be scattered in the wind to reach outlying populations in more favorable growing areas. Have you ever noticed that your earliest and tallest plants are generally males??
Now with that in mind, there are hormones like auxins, cytokinins and gibberellins that promote growth. Now gibberellins or (GA) is the most powerful growth promoter because it increases internodal spacing and also promotes flowering in many ornamental plants, but most of those plants turn out to be males. When too much direct wind is hitting a plant, the reason it creates "stronger stems" is because it creates stress, which in turn, creates more GA and the plants develope stems with smaller internodal spacing (stronger stems) but could also create more males.
We cannot compare cannabis to humans or animals, but we can compare cannabis to other plants where alot of scientific experiments have been done with growth hormones and environmental conditions. Again, this is a theory, but its widely accepted throughout the horticulture and botanist community. I know there is very little to no experiments being or been done with cannabis, but there is alot of experiments done with other plants that are alot more closely related to cannabis through there genetic makeup compared to humans or animals. Just my opinion.