When I first started practicing law, one tool in establishing paternity, or more accurately, lack of paternity was done by blood testing. This would rule out paternity, but not establish. Later in the 1970s, the main tool in establishing paternity (or lack thereof) was the HLA (Human leukocyte antigen) test which could rule out paternity and narrow down likelihood of paternity when the simple blood typing analysis broke down and couldn't rule out paternity. HLA testing is done today in organ transplant suitability. In the 80s, DNA analysis began developing and has progressively gotten better over the years as more and more alleles could be compared. I defended a rape case involving a 1 and 600 quadrillion analysis that established the frequency of the tested alleles of dna in the general population compared against his and that found near the victim's cervix. Here's the image of a quadrillion pennies stacked in space.
https://www.google.com/search?q=quadrill...280&bih=579
