Gender is determined by chromosomes, which are inherited from parents. Therefore, if you want to conceive a girl, you must ensure that the mother's chromosomes are of type XX and the father's chromosomes are of type XY.

Another factor that may affect carrying a girl is a woman's body temperature. Research shows that women are more likely to conceive a girl when their body temperature is elevated (usually when body temperature rises between 0.5 and 1 degree Celsius). This is because when body temperature rises, a woman's body is more open and more likely to combine with a man's sperm.

However, these studies cannot completely determine the probability of having a girl, because these results may also be due to chance. Furthermore, these results do not apply to all women and all conditions. Therefore, if you want to conceive a girl, the best way is to maintain good living habits, such as eating healthy, exercising, quitting smoking and drinking, etc., and having regular prenatal check-ups.