The Chinese birth calendar was discovered relatively recently, and  had been buried in a Chinese tomb for 700 years. It is now on display at Beijing University and is something of a curiosity, although many people rely on it to predict the gender of their children. It has been said the Chinese birth calendar is 93% to 99% effective, although there are many who claim that it was not predictive in their cases. The Chinese Birth calendar looks quite simple and predicts whether a baby will be a boy or a girl depending on the mother's age and which month the baby will be born.

Although ultrasound is the main device for indicating the gender of the baby, there are often mistakes in ultrasound exams, and many girls who have been born in recent years were thought to have been boys in the womb and vice versa. In addition, many more people are avoiding having routine ultrasound performed because of risks to the fetus and for religious reasons. These people do not have other means of predicting the gender of their babies and may use the Chinese birth calendar to see whether they are having a boy or a girl. The Chinese birth calendar enables a couple to know from conception what the gender will be, whereas ultrasound results are inconclusive until the middle of the pregnancy.

It is not advisable to go out and buy all blue clothes or all pink pajamas based on the results of the Chinese birth calendar, but it can provide one with an idea of what gender the baby will probably be. Couples who are really wanting a boy or a girl in particular can plan conceiving their child around the Chinese birth calendar. Based on whether the child will be a boy or a girl in a particular birth month, the couple may try to conceive or avoid conceiving at a particular time.