Is knowing the gender of the fetus, derived from an ancient Chinese calendar, considered a science or charlatanism, and what is the ruling on using it?

The child is male if the man's fluid overrides the woman's fluid, and female if the woman's fluid overrides the man's fluid, based on the Prophet's (peace be upon him) saying: "The man's fluid is white, and the woman's fluid is yellow. If they meet, and the man's fluid overrides the woman's fluid, it will be a male by Allah's permission. And if the woman's fluid overrides the man's fluid, it will be a female by Allah's permission."

Scientifically, gender determination is based on chromosomes. The woman only provides an X chromosome, while the man provides either an X or a Y. If the X from the woman meets an X from the man, it results in a female. If the X from the woman meets a Y from the man, it results in a male.

There is no contradiction between scientific facts and the noble Hadith (definition). Since both Islamic law and science prove there is no relationship between the gender of the fetus and the woman's age or the Gregorian months, using the aforementioned tables (for determining the gender of the fetus) is considered charlatanism, superstition, and impermissible.