Should spelling count?

I’m teaching a neurobiology lab section to juniors and seniors in college. They had their first exam today and asked me if spelling counted.

My first reaction was that of course it does. Part of learning about neurobiology includes learning the correct vocabulary and knowing how to use it.

But now that I’m grading the exams I feel like I’m just unfairly penalizing people for whom English isn’t a first language and who are already struggling.

What do you guys think?