Ok, I grow with non fem seeds and absolutely non-stressed seedlings/plants. I'm not sure if it's a specific strain either as I've only had experience with the one I use. I've noticed that plants with faster developing leaf numbers tend to be males. For example, plants with 1,3,5,7 and so on tend to be males and plants with 1,3,5,5,7 development tend to be female. This is still a study in progress but so far I have 6 plants and the fast developing ones turned out all (3) male and the one slow plant is a female. Right now I have two about two weeks in so no sex yet but one of them is already 'fast' so I'm predicting that will be a male. The other is 'slow' so I'm predicting that will be a female. We'll see in 2-3 weeks. Maybe you guys can keep an eye on this trait with you new plants and see if this method works. Again, non-stressed plants/seedlings cause I'm aware stress through transplant can cause slow down in growth and cause this 'slow' trait. Stable happy candidates only.