The most reliable and obvious way is a paternity test. Most often, the biomaterial on the basis of which the analysis are samples of the epithelium of the mucous membranes of the mouth and saliva. The child has 50% DNA inherited from the mother and 50% from the father. Comparing the genetic code of the baby and the alleged father, it is safe to say, is there between them and biological kinship. The cost of a paternity test ranges from 12 to 20 thousand rubles, and the result will be ready within two weeks.
To determine whether native child grows in the family, a man may in outward sign. In the family of brown-eyed parents can be born blue-eyed baby, but the reverse situation is impossible. There can appear a dark haired girl in a family of blondes. However, sometimes nature plays with people, and some external signs can occur as a result of mutations, but this is the exception to the rule.
If you know the menstrual cycle of his wife, you can try to calculate the date of conception. Ovulation falls on the fourteenth or fifteenth day of the cycle, so most likely, this event occurred at this time. Of course, it is difficult to say who the baby's father, if the woman had contact with two malemi. Well, if you were on a business trip, the answer is obvious.
To determine the paternity, can blood group. For this you need to know your group and group wife and baby. If you are not strong in genetics, download online table of blood groups to see which combinations could be obtained from your source data. Spouses with the second and third groups of blood this method is not suitable, as their child could have any.
Remember that all your suspicions is best to verify or refute the official paternity test. The accuracy of this method is 99.9%.