Is your chinese sexual category prediction correct? chart provided?

Below is a calculator to enter in your birth date, and then the date/year that you had your babe-in-arms -

is it correct?

http://www.chinesefortunecalendar.com/Pr…

Nope, say Im having a girl but Im actually having a boy. Due Sept. 13

With my first one it was correct. But I'm pregnant right presently and it's wrong, suppose to be a girl but all the sonograms I had say boy.