The Chinese have been credited with many great inventions not least the manufacture of paper and print, it is therefore no surprise that a discovery in Beijing some 700 years ago uncovered the Chinese Birth Calendar also known as the "Chinese Gender Calendar" . The original chart is often said to be found at the Beijing Academy of Science and Technology, however we have not clarified this and suspect that is not the case
Not so long ago in China the preference of the baby’s gender played a crucial part in life, with many men and women having a preference for the birth of a baby boy to that of a baby girl, so this would seem to be a valid reason for having such a gender predicting chart (The Chinese Birth Calendar) which was probably used to plan the gender of the baby well in advance and often before conception.

However be advised that these tests can only be accurate when the fetus is of a certain age and in a certain position, unlike the ancient chinese birth calendars which claim to predict a baby's gender before conception.
For a long time before we even had such marvelous scanning systems in today's hospitals the only means to ascertain the gender of the child within the womb was done in some quite remarkable and peculiar ways, the use of dowsing for example was no doubt one of the most popular and well-liked customs. In its simplest form this comprised of a stick with a bit of cord tied to one end from which a ball was attached, this would then be held above the woman's abdomen and the gender of the fetus was defined depending on which way the cord and ball rotated.
The Chinese Birth Calendar also known as the Chinese Pregnancy Calendar calculates it's results based upon a woman's age and the month of conception, it is done by drawing two straight lines on the chart one horizontal relating to the woman's age and one vertical for the month of conception, the spot where the lines meet is the forecast result of the gender of the baby.
While we cannot guarantee or even vouch for the accuracy of the predictions to which this chart makes, we have learned that it is extremely accurate. The chart can be found here Chinese Birth Calendar