Thousands of years ago the Chinese developed a calendar to predict a baby’s sex. It was supposedly discovered buried in a royal tomb about 700 years ago and is said to be over 90% accurate when used correctly. Of course, this is really just for fun — but we would love to hear from you (and we are sure many pregnant mamas would as well) whether the chart is accurate for your past births. Please check the chart and tell us about the prediction(s) in the comments below! How Do I Predict My Baby’s Gender Using This Chart? It’s simple: start by finding the mother’s age at conception across the top of the table and then follow that age down until you come to the month in which conception occurred along the side. A blue box means boy and a pink box means girl. To use the calender correctly you will need your Chinese lunar age at the time of conception. To find that you can use the calculator on this page. Just type in your birth date and the date of conception and it will give you the correct age to use. Please note: Mothering is not associated with the site that hosts the calculator. So, was the chart correct for you? Tell us in the comments!