When you switch the lighting cycle to 12/12 then you are looking for little white hairs(female) which is what you want, or little balls, kinda like a bunch of grapes(male) at the internodes(what you described). Whenever you want to, you can change the light cycle to sex the plant. If its a female and you want to grow it a little more then you can return it to veg cycle by switching the light back to 18/6 or 20/4. If not the start flowering and let the fun begin. Oh yeah and if its male go ahead and cull it because you wont get much out of it unless you are trying to breed, which im assuming you arent. Good luck bro -Diz:rasta: