Many parents long before the birth of the child want to know next color of his hair. Theoretically it is possible if to know some laws of genetics. And even tests any should not be made.
1. In the course of formation of hair color of future child, genes of both parents participate. Notice, any genes including responsible for pigmentation of hair, can be either prepotent, or recessive. In other words strong or weak. In the course of origin of future person the strong prepotent genes block action of weak recessive and are transferred to future generation. That is, if the father has a hair color gene prepotent, then it also will be inherited by the son or the daughter.
2. If both parents have prepotent or recessive genes, then "result" of their "fight" will be unpredictable. Genes of grandmothers and grandfathers can interpose in the matter, influencing a result. In this case the hair color of future kid can be defined only with the known share of probability.
3. Independently it is possible to determine a factor of dominance or recession of the genes by the following signs. If you have brown or green color of eyes, a normal factor of fibrillation or tendency to baldness (at men), genes prepotent. Recessive genes are characterized by a straight hair, lack of pigmentation of skin and a negative Rhesus factor of blood.
4. Do not forget that the genetics is not mathematics. She does not give exact answers to questions of heredity but only she defines the most probable opportunities. But process of transfer of genes can join genes of relatives of several generations. As a result absolutely unexpectedly in family the red-haired child who inherited hair color from some distant relative is born. Especially often it occurs at the firstborn's birth.
5. Also do not forget that within 5 first years of life of the newborn the hair color can exchange and not once. Usually they change in first or second lives and are finally formed to age of 5 years. But during puberty because of change of amount of testosterone in the teenager's organism the hair color can change once again.