Pre-flower Sexing - HELP PLEASE?

Hi everyone. For those that haven't come across any of my posts - I'm new to this forum and have some experience growing, lots of general botanical book smarts (thanks to my college career) but not a huge amount of cannabis cultivation experience. Though I do work with my old prof from time to time running experimental protocols on some cannabis plants (he has a license to grow through the university - cool!).

Ok - so I was checking out my not-so-babies-anymore and was a little surprised to see preflowers well developed on two plants and not the rest - all same aged plants in same growing conditions. Anyway, I am posting pics of them in the hopes that someone can help me with sexing. I've never sexed via preflowers before, I always either get feminized seeds or clone a good mother plant.

Oh and I should mention some of the experiment: the interest is to look at how stressing a cannabis plant through topping it prematurely will affect bud development. He asked me to take two plants (small single replicate study - more a proof of concept than anything else at this point), different strains, not sexed, and top them at the 3rd node. He's looking to see how the plant responds to this stressor. Interestingly these are the plants with the most developed preflowers - all plants in same soil/nutrient conditions, monitoring pH and other parameters (for publishing later), same light conditions - outdoors in same garden, and all started at the same time - about 30 days old). Since they are growing at the meristem on the main stalk as expected - though slow to respond and they do not look as if they biped - I'm curious if the stress has forced them to show their sex early and if this can be modified later as a way to determine sex quickly without harming the plant (of course that much remains to be seen).
Sorry all the pics are from my iPhone. I have to get my digital microscope back from my friend and I'll post those pics later.

I doubt you and your " proffessor " have any sort of cannabis knowledge. Because if you even took the time to research it, like any other project, you would come to find out that plants grow leafs from the stems. In between where that extra chunk of stem you left out, which you should pinch it off not snip it off. When you top, it simply means you are allowing the two leafs that are growing in between to develop bigger and stronger stems, by being at the top. Also it is used to get bushier leaves, by using an LST method and by having a ScrOG installed. But im sure your universiry prof knew that. Do some research, please. Are you a troll? Is this really real?

"Fuck, YOU missed."

You don't have any preflowers

Yeah, that's just new growth. Pre-flowers are unusually on the fourth or fifth node. Sometimes (depends on the strain) you get pre-flowers @ 3-4 weeks.

Those are new leaves coming through... not anything to do with sex.

omg

Let them grow and all will show itself

Just a quick update...so I left them to grow doing nothing but giving a general grow nutrient, water and as much sunshine is available outside in my lat (plenty it's summer here), been hot and humid except past several days have been chilly and rainy, a nice good deep soak for the roots. It's warming up again now so I'm thinking I'll see some explosive growth. anyway, here's what happened with the pinching experiment: the one I did as per normal procedure did as expected and biped. The one I pinched below the 4-5th node and left left a piece of the stem below the pinch, at the node, did not double. It gave me three distinct heads, all shooting up on separate stems from the node. Looks cool. See pics. Anyway, good luck, things going well for me and I hope for you all too!