Very true. Also once they reach a certain age in there vegetative stage...24 hours of light has been proven to promote male traits...and hermies in females. High times said that 18 hours of light and more will do this...i'm going with 16/8 this run, and see how I fair.
My first 3 grows were 2 plants each. I was growing from clones though and was fairly sure (hermies aside) that they would be females. It was plenty to manage as I learned. Was doing four clones and 2 bagseed this time around and both bagseed turned out to be males. What a pity......