Doubts in kindred with own child can arise at the man and till the child's birth, and on the eve of his majority. Fortunately the medicine allows to establish paternity rather precisely today. The word in this ticklish business tells also the law.
1. If you had doubts that the child genetically is your relative, for a start frankly talk to his mother. Perhaps, your former spouse will not begin to deny your non-participation in the son or the daughter. In case of mutual consent of both parents, modification of the birth certificate of the child is by a court decision allowed. It is more difficult if you want to disprove paternity, and the mother insists that your child. In this case your way lies in court.
2. If you are sure of deception from the spouse, submit the statement of claim to judicial authorities. This right is granted to you by Article 52 of the Family Code according to which to challenge paternity or motherhood only the faces which are written down in qualities of father/mother or actually being parents and also the child on reaching majority can. For effective protection of the interests you will not be prevented by the help of the good lawyer. Collect evidential base which will confirm that you could not be the child's father (for example, a long time were in a business trip and actually did not live together with the estimated period of conception). In the absence of incontestable proofs of you the court has the right to appoint genetic examination, but only with the consent of the child's mother.
3. In some situations the law does not allow to challenge earlier established paternity. So, if you at the time of paternity proof knew that this child is not your biological son or the daughter, it will not be possible to cancel entry in the birth certificate. The same concerns the children born with application of donorship, implantation of an embryo and by surrogacy from your written consent.