Male??? Female??? HELP!!!

Hey im a new grower and was wondering how soon you can tell if yor plants r male of female. Heres some pics ()xxxxx};;;;;;;;::::::::>

they need a couple of weeks of 12/12 light before you can tell

I usually don't see any indicator of sex until well after the 7th internode.

Alright thanks. Thought maybe cause one had fat dark green leaves and the other had skinny light green it might have been an indicator

those leaves indicate strain