Most if not all medical and scientific studies that are performed on humans are flawed.  This is because they have a core assumption that all of the human subjects in the studies are in fact real humans.  We know that this assumption is false—various species of non-human shapeshifters who can assume human forms (stars) also exist in the population.

Some of these shape shifters are avian, canine, feline, lupine, or reptilian, and some are other types of shape shifters such as insects.  Within these categories, there are various sub-types.  For example, there are many types of reptiles.  Medical and scientific studies fail to account for these inter-species and intra-species variations.  In other words, the studies with human subjects erroneously assume that all of the beings are humans, when in fact, many of them are not.  Therefore, these studies are flawed.