GURPS Star Trek - Canon Vulcans

[Inky]

Occasional hassle about the special requirements of alien crew members does seem to crop up in Star Trek, but mainly just at a "local colour" level (again possibly standing in for catering for a crew of many different nationalities).
It's possibly kind of implausible that the difficulties are as small as they are (small enough for having different species on one ship to be practical), but the premise might not work otherwise.

For instance, there's one episode (not sure what series) involving a human who has to use a wheelchair on board their ship because she grew up on a low-gravity world and can't handle normal gravity.

It seems like the Klingons possibly can eat normal food, but if catering for Klingons turns up it's usually in the context of precarious diplomatic negotiations, so if they want raw meat and live worms that's what they get. Similar position with the Ferengi.

And, of course, McCoy seems to frequently grumble about not being able to make sense of Spock's physiology, though some of that may just be McCoy taking the mickey - at one point, he takes Spock's pulse (240 bpm or something silly) and then asks him if that's the right answer, or words to that effect, and McCoy seems far too competent a doctor to have set out on a long voyage knowing that little about one of his patients.

Seriously, though, if the differences between the alien species were more than trivial, a doctor's job on a ship that had more than one or two aliens on it might be completely unfeasible. There might be some overlap between species, but realistically, you might need a different doctor for each species, which might be enough to make just not having mixed crews the easier option!

Replicators might make a big difference to how practicable multi-species crews were, as the computer could just be set up to provide each crew member with food that was suitable for their species.

On ships with Ferengi or other mini species on board, it seems like hassle over providing suitably-sized chairs, equipment, etc. might be part of daily life for the maintenance crew!

I suppose in a game setting like Star Trek, it might make sense to just give all the characters 0-point Unusual Biochemistry relative to each other, the same as how what your temperature range is is a 0-point feature (this may already have been said). Of course, the alien not being poisoned by something that is poisonous to everyone else is possibly as common a plot twist as the other way around - I'm not sure whether there's anything in the rules that covers that.