The Ancient Chinese Gender Prediction Chart is said to help parents predict the gender of their baby based on the Mother's age and the month of Conception. This chart is said to have been drawn by a Chinese scientist about 700 years ago. The chart has been taken from a Royal tomb near Peking, China and the original copy is kept in the Institute of Science of Peking. The accuracy of the chart has been proved by thousands of people and is believed to be 99 percent accurate.
Also while doing a check u need to keep in mind that the chart is based on lunar calendars which are 29 days in length, so instead of confusing yourself, you may just use this
http://www.chineseastrologyonline.com/PredictSex.htm
and you may have the chart for your reference