The males need to be totally removed as soon as you know FOR SURE that they are in fact male... I would definately only determine sex by actually male or female flowers... i've grown out seeds and all were different sizes and some tall ones were male, and some tall ones were female...not saying you can't tell, but wikid is right, it's not 100%... I wouldn't keep those males at all, because if one microscopic little piece of pollen gets in there you will have seeds and it might only be 1 but it might be 100 as well... if you're growing for smoke, toss the males, if you're growing for genetics, start another sealed grow box in another room from the females... pollen goes a LONG ways in nature, it will travel in your house too! goodluck! hope the bud if fire!