You're kind of in a tough spot, as your request and the answer is complicated.

First off, kind of unrelated, gloves are not necessarily required by most health codes. Recent findings are that when required to wear gloves, people wash hands and change gloves less often than when not required (causing more frequent hand washing), so the rules on glove requirements were relaxed.

Second, in any restaurant at any level, some portion of your meal was prepped ahead of time by someone else who is not actually preparing your meal. There were some carrots diced, chicken grilled, salad mixed, or potato peeled by someone who might be wearing a glove, and that is something you will have a hard time getting undone. So you can most certainly ask that the chef not wear a latax glove when preparing your meal, but like a peanut allergy warning, 'some latex gloves may have been involved with the preparation of your meal'.