I recently bought a product called Flower Seed Soak,
It consists of Ethylene acid, Alginic acid and Vitamins.
It claims to Stimulate the seed to encourage a tendancy for the plant to become female.
Directions: Wrap seeds tightly in WHITE tissue paper and fold over 3 or 4 times, wet with Seed Soak
and place in a plastic zip lock bag for no less than 24 hours and no more than 30 hours.
Well I tried this several times but only my freshest seeds remained viable after soaking,
they were a cross of Lowryder 2 and Durban Poison Autoflowering that I bred myself.
The final result?

3 females and 3 males, not so good, so since they are auto's I'm using I can keep experimenting
and I only need to wait 3 weeks for sexing.
I have another 12 soaked seeds popping today so I'm trying again, but this time I'm also using La Femme as well.
If I get 12 females I'll be a happy chappy but we'll see.