I been studying that pic like a hawk and i can still not see anything. I can almost be positive that plants not old enough to show pre-flowers under veg yet.

The lights are ok, the plants not stretching, thats the thing u have to look for...

If you wanna know the sex, then put the lights into 12/12 and then after 2 weeks you should see...

If your still in doubt, post more pics, but only when its been in 12/12...