The judge is supposed to determine which evidence is allowed. The jurors only need to understand the evidence to the extent it proves guilt. Given new science

The judge is supposed to determine which evidence is allowed. The jurors only need to understand the evidence to the extent it proves guilt. Given new science, the prosecution and defense make their case and the judge allows/disallows the evidence. But, the judge isn’t a scientist, she’s a lawyer (if we’re lucky - some parts of the US have elected judges with little to no professional requirements). And the prosecution might have more money and better experts.