True, it's always best to get some 100% feminised seeds from serious and devoted seed companies.
I took a closer gander at your pic and noticed another male/hermie in the background. If that one is a hermie too, then you're probably stressing your plants.
Plant stress is caused by too high/low temps, extreme variations in pH/nutes/light/temps or through over/underwatering excessively (or, if you have a mother like mine, letting your mother nag your plants
- huge source of stress for plant and grower
).
By the way, I also noticed you're using aluminum foil...most growers suggest not using this, cause it can heat up and cause heat damage if you're using a powerful lamp (over 400W HID).
Tell us, did you have any of the above problems (temps, light cycle screw up, pH, watering screw up etc)? And if not..where did you get the seeds from?