There is the European method of determining the sex of the baby depending on birth dates for parents. It is based on the theory of blood renovation. It is proved that the men blood is updated once in four years, and the blood of women every three years. Whose blood at the time of conception will be the younger child of that gender and work.

Divide the age of the father of the child to 4, and the age of the child's mother at 3. If the result of dividing the men or women turned out an integer, then the blood of his recently updated. Accordingly, the chance of conceiving a child of the same sex with this parent is very high. If integers did not work, then you need to look at the remainder value. One of the parents it is smaller and has a higher chance to conceive a child of the same sex with him.

Just keep in mind that the blood can start to upgrade and after difficult situations - injuries, surgeries, childbirth. In this case, as the starting point you need to take the time of the last blood loss.
How to determine sex of baby by date of birth of parents can be due to another way - Chinese. This method is considered the most reliable. It's hard to explain how it works, - it takes into account many factors that affect the conception of a child of a particular sex.
Relate the mother's age with the month in which she is going to have a baby. For this you need a special table, which is called "Chinese table determine the sex of the child." It can be found in the Internet or buy in a bookstore.
And finally, the Japanese way of determining the sex of a child on dates of birth of parents. You will need a special table and a Japanese calendar. In the table horizontally a given month and date of birth on men, and on a vertical - the month and day of birth women. At the intersection of these two dates you get the number that you will need to substitute the Japanese calendar. He will give you the most favorable time for conception of a certain gender.

In fairness it should be noted that the Japanese themselves attribute this method to be more to the folk than to the practical.