GAW: The Tzitz Eliezer has a T’shuvah (in Chelek 14, I think) about using blood type for paternity. He knew the medicine, but rejected it based on the Aggadta that a man gives the white part of the baby (bones and skin) while a woman gives the red (blood), thus blood type can’t prove paternity. R’ Moshe Shternbuch has a T’shuvah (chelek 4 in the middle, I think) that says that blood type and DNA can’t prove paternity because maybe the doctors will realize 50 years from now that this really doesn’t work.
Both of these Rabbonim know the Metzius. These are just more examples of where we reject any new way to create Mamzerim.
There were a few articles published post-9/11 with the concern that if we use DNA as a S’nif to be Mattir an Aguna, then it would mean we have to be Chosheish for it for Mamzerus issues. Poskim still came out (I think R’ Elya Svei was one) and made a Chiluk that you can use DNA to prove that a person is this person but we don’t know enough to use it for paternity.