This will be on every CannabisTube talk shit shows in a few hrs. lol
I see this is gonna turn into to a "shit show". lol
Ok, you all do this,
Go look at your plants that are between 2, 3, and 4, weeks. Start with your 4 week plant first.
Take an instrument or finger and pull the stipule away and look inside where the bract should be and the secondary top.
If you see nothing, possible female or male
If you see a tiny tiny tiny yellowish/white speck
about the size of a "pin" head, not a "pen head".
Chances are that one will be a male plant.
Now...
if you look and see a tiny "green" speck.
Chances are very good that will be a female.
You don't need a magnifying glass, learn to see it with your own two eyes.
Once you recognize what you're looking at, it gets easy.
You will notice your males earlier.
I've been checking plants this way for many years.
If you can knock 10 days off your transplant schedule creates more room and no wasted space.
Seriously, it must have something to do with Chlorophyll absorption between a male and a female in that stage of growth.
That's all I got for an explanation of why it works.