According to the Pregnancy Board, baking soda is the perfect DIY gender prediction test.
You will have to put a little bit of soda in the disposable cup and put a small amount of your urine in it. If it frizzles like a soda pop, then it may be a boy, but if it does not frizzle, then it may be a girl. This test has been used for testing the gender, and 22 out of 31 have been correct, while only 9 were wrong.
This may be a fun method to try out along with some old wives tales for predicting gender.