you cant tell the sex of the plant with only 2 sets of leafs,impossible,unless its a clone and even then its hard with just 2 sets,only way to to check is either veg them out for 4-5 weeks and you should get pre-flowers,
this is a good way but can also be missleading for a new grower...

the other option is to grow the plants then take a cutting and root/flower it out and what you get is what you get..

your friend must be growing super weed that talks to him..

i no i will never buy feminized seeds again, buying regular seeds and doing the old fashion way is alot better but can be a pain in the ass..

and if you buy regular seeds from a top breeder you will have a high f/m ratio from my experiance....plus you can also breed them and make more of them seeds.for future grows/storage....