So that I can understand the question:
This is a chemistry class, but you are supposed to do a paper and teach the class on a matter having absolutely nothing to do with chemistry, such as your examples?
Or were your examples intended simply to be examples of things that are controversial, but the need is to have something controversial in chemistry?
Right now I can’t think of anything controversial in chemistry that would be suited for introductory courses. For example in a more advanced class, Pearson’s hard and soft acids and bases analysis versus the chemogenesis model would be a good subject, but not appropriate for an introductory class.
Introductory matters are pretty clear ones: that’s the problem.
You could, along the same lines, do Lewis acids vs Brønsted acids, but that’s not controversial.
Vaguely chemical would be whether dietary sodium increases risk of high blood pressure. But that really is not chemistry, it’s biology. It is at least a little chemical-flavored though.