boy or girl?

I came across this Chinese Lunar Calendar online which supposedly accurately predicts what the gender of a child is going to be based on the mother's age and the month in which the child was conceived. From what I can tell, I think it is accurate for 3 out of 4 of my mom's pregnancies (but I'm not sure if I have the ages right). For those of you who have had kids (or are pregnant and already know the gender of the baby), is it accurate for you?
Note: I am in no way, shape or form announcing anything by this post. It is merely for curiosity/fun :)