What is the ruling of Islamic law regarding the children of concubines born in 1925, and is it permissible to resort to medical analysis to prove the lineage of children of one of the wives who are accused of being born out of wedlock? And is there any sin in that?

Every child born to a wife or a slave woman with whom her master has intercourse is attributed to him if the period since intercourse is at least the shortest gestation period (six months). The proof for this is the saying of the Prophet, peace and blessings be upon him: "The child is for the bed, and for the fornicator is the stone." This includes a man's children from his wives and his slave women. It is not permissible to deny their lineage to him as long as he acknowledges it. Blood analysis for proving or disproving lineage is not considered Islamically valid. Accusing a chaste woman of adultery or denying the lineage of others are among the gravest sins.