Hi Shiva
I've been watching your grow diary for a little while - very interesting as i'm about to start my first grow (I have a 400w HPS, 15 sensi skunk seeds, and Hesi nutrients). Your ladies are gorgeous, congrats!
About determining sexes (not to spoil the fun of waiting, but...), one way to do it is to take a clone from each plant, get it to root, then force them to flower in a seperate light regime (to do it in the same place, just cover them in somehting opaque for 12 hrs/ 24) - because they are genetically identical to their parent, they'll show you the parent sex without you having to stress mummy (/daddy) unduly.
Have you been growing under fluorescent light all this time? I'm thinking of incubating the seedlings on a windowsill then transplanting when about 5in high into the large pots and put em in the main grow area, what do you reckon?
Cheers