Maybe, maybe not. He will never find out cause he pulled them out. Does he every find any males when they flower?? If so, he might have destroyed a few females as well. generally, after starting flowering the males do look the healthiest and flower first. Nature. VV
Dude there is no need to try and pull early. I'm sure multiple things effect every seedlings efficacy... just grow them, spot pre-flowers or immature flowers during early flower and have fun... I did it, worked perfectly. No pollenation. You can snag the ones wth pods before they open...