I used the Femta (www.femta.com I think). It tracks your cycles, and is based upon the theory that during certain times your ph changes. "Girl" sperm and "boy" sperm are different- boys are quick but die sooner, girls are slow and steady. So the ph affects which ones get through. Make sense? Anyway, it's a downloadable application that shows you which days you are more likely to get pregnant with a girl or boy. I have a baby girl, and it may have been a coincidence, but I think it worked for me! Good luck!