“13. What are the consequences of the impossibility of assigning a statistical weight to the voids? The alternatives are to exclude the evidence entirely or to admit it subject to an appropriate warning to the jury of the limitations of the evidence, and particularly highlighting the fact that although what was found was consistent with Bates’ DNA profile, the voids at D2 and D18 in particular may have contained an allele or alleles, the presence of which would have been wholly exculpatory. 14. In arriving at the correct conclusion it is important to remember that scientific evidence frequently only provides a partial answer to a case, or to an issue in a case. However, the test of admissibility is not whether the answer is complete, but whether science can properly and fairly contribute to the matter in question. . . . . . . . . ”