How the Chinese gender chart works
The chart is a table of 336 answers. It reads two numbers: the mother's lunar age at conception, from 18 to 45, and the lunar month of conception, from 1 to 12. Where the two cross, the chart says boy or girl. Both numbers are counted on the Chinese calendar, which is where quick versions of the chart go wrong: a date in January usually belongs to the 11th or 12th lunar month of the year before, and the lunar age is not the everyday age.
Working out the lunar age
Lunar age counts the Chinese year of birth as 1 and adds a year at every Lunar New Year. A mother born on April 12, 1995 was born in the Wood Pig year, which began on January 31, 1995. On June 3, 2026, in the Fire Horse year, her lunar age is 2026 − 1995 + 1 = 32, while her everyday age is 31. Had she been born on January 20, 1995, before that year's Lunar New Year, she would belong to the Wood Dog year of 1994 and be 33 by lunar age, and for a June 2026 conception the chart's answer would change from girl to boy.
Finding the lunar month
Each Chinese month begins on the day of a new moon, dated in China. June 3, 2026 falls in the 4th lunar month, which runs from May 17 to June 14, 2026. The predictor holds every Chinese month from 1950 to 2050, including the leap months the calendar adds about every third year, and the table below the chart dates the months of this year and the next.
How accurate is it?
Researchers in Sweden checked the chart against 2,840,755 births from 1973 to 2006 and found it predicted the baby's sex no better than tossing a coin, whatever the mother's age, education or number of children. The study, by Villamor and colleagues, appeared in Paediatric and Perinatal Epidemiology in 2010, and its authors advised against painting the nursery based on the chart's result. The chart also leans slightly toward girls, with 172 of its 336 cells saying girl, while slightly more boys than girls are born everywhere.
The Mayan method
Another folk predictor, often called the Mayan gender calendar, uses the mother's everyday age at conception and the month of conception, January being 1: both even or both odd reads as a girl, one of each as a boy. Some sites use the year of conception instead of the month. The predictor shows the month version beside the Chinese chart's answer, for comparison; it has the same standing as the chart.
For a certain answer
A prenatal blood test that screens the baby's DNA can show the sex from about 10 weeks of pregnancy, and the anatomy scan at around 18 to 22 weeks usually shows it too. Your doctor or midwife can tell you which is offered where you live.