I've taken that into account. Other than the non-humanoids, most of the people I've seen appear to be amino-based life forms otherwise their basic genetic make-up would make it impossible for them to survive in our environment. The only difference I can think of is the instances of certain alien species here that have slightly altered amino acid sequences in their genetic structure - which can be accounted for with proper experimentation by creating a one time virus that targets the vessels in one's nose to rupture, then immediately seal the blood vessel.