Think I might know what led to your question. I've been growing for 41 years, & back in the day, it was believed putting them under 12/12 before 8 wks old would stress them to be males. I never questioned that, took it for fact & went with it untill I came to this forum. Really glad I came on board. The info here has debunked a lot of old myths & wives tails. From now on I'll be putting the ones I need to keep sm into flower (12/12) as soon as they are 6" tall, regardless of age. But read everything & ask questions. But yeah, having a B.S. in horticulture didn't protect me from falling victim to the wives tales.
---B.T.W. Shovelhandle busted that myth for me, don't think I thanked him for that. The most usefull info I've had. So thanks Shovel ! Oh, & I did give you reputation points for that! ~~~PEACE! ~~~