Look for pre-flowers at the nodes where branches meet the main stem
Male plants usually form small round pollen sacs
Female plants usually form teardrop-shaped calyxes with two white hairs
Male sacs often appear in clusters and point downward
Female pre-flowers usually sit closer to the stem and look more pointed
Males typically show sex earlier than females
Females may develop more visible pistils as they mature
Remove male plants if you want to prevent pollination
Use a magnifying glass to inspect early growth closely