Gender is based on the DNA provided by the father. That's it. A woman's diet, cycle, etc. won't make a difference. Unless you are going to get into genetic manipulation or in vetro, you've got a 50/50 shot.
Lol, I think everyone knows that! These methods are based on a theory that male DNA sperm and female DNA sperm having different swimming speeds, and different survival lengths. Therefore, when you ovulate, and when you BD makes a difference (with this theory).