Hyroot - Other than the one Vortex that refused to show sex, all the TGA seeds I've run have shown sex at around 24-30 days since sprouts popped above soil (24/0 or 18/6 lighting). I use a 30x jeweler's loupe to inspect the tiny preflowers closely. At that point the female preflowers don't have pistils yet, but I can tell by their teardrop shape. The fem preflowers also tend to stick straight up (hugging the main stalk), while the male preflowers often stick out kinda sideways from the node.