It;s an established fact that people who stutter are more likely to stutter on longer words and words that have high "propositionalilty" (e.g., more meaning, ergo more specificity). You're battling two fronts, the meaningfulness of the word (scientific meaning) and the number of syllables (scientific names tend to be longer) More to the point, if your peers laugh at you, you should confront it directly. "Yes, I stutter" (perhaps add in an eye roll, not necessary, but be confidently annoyed). This demonstrates you're aware of your stuttering (obviously), but the eye roll demonstrates they're not the first person to point out irrelevant information. And the fact that you stutter is certainly irrelevant to doing your job.