How the Mayan gender predictor works
The Mayan gender predictor compares two numbers: the mother’s age at conception and the number of the month in which the baby was conceived (January is 1, December is 12).
The rule
If both numbers are odd, or both are even, the prediction is a girl. If one is odd and one is even, it is a boy. A mother aged 27 who conceives in May (month 5) gets two odd numbers, so the answer is girl. A mother aged 26 who conceives in March (month 3) gets one even and one odd number, so the answer is boy.
Regular age, not lunar age
Unlike the Chinese chart, this method uses ordinary age in years and the ordinary calendar month.
Month or year?
Most sites use the conception month, and so do we. A smaller number apply the same rule to the year of conception instead, so you may see different answers elsewhere.
Is it really Mayan?
It is often credited to the ancient Maya, but we could not verify that, and at least one site says there is no documentation that it is actually Mayan. Some sites that look at accuracy put it at about 50 percent, the same as guessing.