The easiest option is the Japanese system. The essence is to use a specialized table. Vertical will indicate the day and month of birth of men, and vertically from women. You need to find the intersection of these two indicators. There you will find a number. Substitute it in the Japanese calendar. As a result, you will receive a chance to get a baby of a particular gender.
To find out the sex of the child age of the parents will also help the Chinese method. Considered to be the most reliable and tested, because when counting takes into account many factors that can affect the sex of a baby. Map the data that is required in the Chinese table determine the sex of the child. It can be easily found in a bookstore.
Also often used the European method of determining whether you have a boy or a girl. The essence is that the blood of men and women unequally is updated (every four years, and every three years respectively). The child's gender will affect the blood that will be younger. Divide the current age of the parents at 4 and 3 respectively and see which numbers work. If blood is younger than the man, then a boy, the woman – girl.
If you want to get more reliable results, turn to the experts.