How can a son's lineage be confirmed? Should the word of a father, known for his frequent lying, be accepted that he begot the son after the legitimate marriage contract? And would the testimony of an apostate, immoral mother be accepted in proving this, so that legal rulings such as hijab and others may apply?

A man is to be believed if he claims that his son was conceived from a previous legal marriage contract before the civil contract, or that he was born out of wedlock and he attributed him to himself. However, if evidence strongly suggests that the husband is lying about the child's paternity and that he is not his son, then the child must be veiled from him and not be left alone with him. The child belongs to the marriage bed (firaash), and if a child is born on the husband's marriage bed and he does not deny paternity through li'an (oath of condemnation), then he is his son.