anyone knows if this method works? sexing a not yet rooted clone

Hi all I have 3 AK47 and one Critical Mass plants, vegging in soil from seeds, 15 days old. I was wondering which is the best method for sexing them, because I want to keep the ladies and use them as mother plants
Actually the flowering room is working with a long flowering sativa.... at least two months from now before harvesting

So th question is: can I cut a clone, put it into the water and directly transfer it to my flowering room, even if it's not showing roots yet? Will this little clone show sex after a week or so?

i think a week or so will show sex of 18/6

12/12 for sure ......but the clone has to be a sucess with signs of growth or root developement

leojapsky, you mean to keep the clone a week or so in 18/6, waiting roots developement and THEN put it in a 12/12 flowering cycle? yes, I know that if the clone is rooted, it can show sex, but......

My question is can I put this clone 12/12 IMMEDIATELY after cutting

c'mon guys, how do you sex your plants

which is the best method?