Legal DNA testing can be used to solve issues of parentage in cases where one parent is contesting the issue. You may need to fill in a declaration of parentage. The Child Support Agency (CSA) and the Child Maintenance Service can use DNA testing to solve disagreements about parentage. The costs will always be incurred by the test participants although in exceptional circumstances you may request a refund or a fee exemption. A DNA test will establish the probability that the parent tested is the biological parent of the child. The probability results in a legal DNA test can be either of 0% in cases where the alleged parent is not the biological parent or 99.99% in cases where the tested parent is the biological parent.