That's the thing. You purchased feminized seed, so your plants will be female. Now yes, they could turn hermie, just don't stress them to much and you'll be fine. I've grew out some Afghan Kush Ryder (see my avatar and sig pics) from Attitude and lst'd the crap out of them and they didn't turn hermie. As for changing the sex later, Missnu is probably referring to using Gibberellic acid to turn a branch from female into male so you can have self pollination by a female resulting in your own personal stock of feminized seeds. I'd suggest not worrying about that for now and grow them auto's out! Give 'em 24 hours a day of light, 1/4 strength nutes, and read up on systemic resistance. I had great results with mine. Hope this helps!