hell yea try this....
start some seeds... mark ALL plants like 1, 2, 3, 4, 5, 6, 7, etc.....
then during veg week 3-6 take clones from each plant and label which clones came from which plant like 1-a, 1-b, 1-c, 2-a, 2-b, 3-a, 3-b, etc. etc.
then take all mother/father plants that you took cuttings from and slap in 12/12 so you can determine sex..
if you determine that plant 1,3,5, and 7 are females then you know that all clones taken from these plants are females. and if you determine plants 2,4,6 are males then all clones taken from those plants are males and need to be culled/killed/removed w/e
this process avoids having to switch to 12/12, determining sex and THEN taking clones.. you can take the clones when the plants are veggin away..
just make sure you keep track of which clones came from which plants or you will be screwed!!! lol
hope that helps!