Female traits
White pistils or hairs indicate female sex on the poster.
A teardrop calyx houses the pistils and becomes part of the future bud.
Other female cues listed
bud sites forming, tighter node spacing and strong resin production
Male traits
Males are shown with round pollen sacs in clusters and no pistils.
The sacs hang downward and eventually open to release pollen.
The poster says males are usually taller and stretchier and should be removed unless you are breeding.
Hermaphrodite traits and causes
Hermaphrodites are shown with both pollen sacs and female pistils on the same plant.
Stress causes listed
light stress, heat stress, nutrient stress, environmental stress, physical stress and end-of-life expression
The breeding note says intentional reversal using STS can be used to create male flowers on a female for feminized seed production.
What to do if you find a hermie
Remove visible pollen sacs immediately if possible.
Isolate the plant from others.
Monitor closely because more sacs may appear.
If severe, remove the plant to protect the crop.