After 2 weeks your plants will still be too young to tell whether or not they are females. The first signs of which sex they will apear after a height of 10 to 20 inches tops in my experience. By the time they are flowering it will be easy to tell the difference. I wont go into detail on how to tell the sex since this info is all over the net.
There is a way to "force" a plant to display its sex early but i wont go into that either as it sets your plant back by about 2 weeks of growth and im sure you dont want that, right?
Peace