BLOOD GROUPING TEST:

     Where the issue is admissibility and conclusiveness of blood grouping tests to disprove paternity, rulings have been much more definite in their conclusions. For the past three decades, the use of blood typing in cases of disputed parentage has already become an important legal procedure. There is now almost universal scientific agreement that blood grouping tests are conclusive as to non-paternity, although inconclusive as to paternity — that is, the fact that the blood type of the child is a possible product of the mother and alleged father does not conclusively prove that the child is born by such parents; but, if the blood type of the child is not the possible blood type when the blood of the mother and that of the alleged father are crossmatched, then the child cannot possibly be that of the alleged father. (Jao vs. Court of Appeals, G.R. No. L-49162, July 28, 1987, Padilla, J.).