"touch DNA" could be causing issues in current forensic analysis. Research has been conducted at the University of Indianapolis proving that it is quite easy for someone's DNA to be transferred to a crime scene without the person being there at all. It is now possible for genetic profiles to be made from merely a few skin cells left, but these genetic profiles prove to be inaccurate.
In a courtroom, "touch DNA" is assumed to be left somewhere from direct contact, but studies are showing that there is no way to know whether or not it was from direct contact or secondary contact. It is possible that after shaking someone's hand, that person could deposit your DNA somewhere else, unknowingly. Because DNA amplification kits have become so sensitive and advanced, a forensic analyst only needs as few as 100 pico grams of DNA to create a genetic profile.
In 2013, Lukis Anderson was charged with murder because his DNA was found under the fingernails of the victim. At the time of the murder, he was in the hospital and the same paramedics took him there that transported the victim. The paramedics transferred Anderson's DNA to the victim most likely. An experiment was carried out by having a pair shake hands for two minutes and then held separate knives, In 85% of the cases, the DNA of the partner was transferred to the knife, and in 20% of the cases the other person was identified as the main contributor of DNA to the knife. This means that it is a very real possibility that this happens in the real world,
With the advancement of technology all the time, this could pose a very big issue. This secondary transfer of DNA could possibly wrongfully convict an innocent person just because they came in contact with someone else. In the courts, the jury is just told that there is a 1 in a quadrillion chance it's not the defendant, but they don't know the process behind it. This definitely needs to be addressed in certain cases of using "touch DNA" as the evidence in a case.