There have been cases in which men are forced to continue paying child support even though ALL parties know that the child is not his. The tests are just fine, it's the justice system that has to adapt. This is a terrible decision and especially tough considering that in most cases the man will have just found his girl has been cheating on him.
Yes, DNA tests are reliable and are used frequently in investigative criminal cases to identify suspects. Therefore, the reliability of a DNA test is important when proving or disproving paternity because it is considered valid in a court of law and used to clear or convict criminals in many cases.
First of all, no one should be forced to pay for a child that is not biologically theirs, especially if they were duped by a woman into thinking the child is theirs. If that is the precedence then the men should be allowed to sue to recover any monies paid out due to false or erroneous information.
With few exceptions, DNA tests have proven to be mostly reliable. The issue at hand is that the law is not always reliable. In fact, in many ways the law remains outdated, particularly when it comes to technology. It is also in favor of the privileged few, causing the poor and disenfranchised to suffer.