The Chinese gender predictor is an ancient method for predicting a baby's sex based on the lunar age of the mother during conception. It uses a Chinese gender calendar to chart the predicted sex according to lunar phases. There are four ways to use the predictor: selecting the lunar age during conception, using the calendar to show the predicted sex, tracking predictions with the chart, and figuring the conception month twice if possible. Accuracy relies on using a Chinese lunar calendar to determine the conception month, which differs from the birth month.