Hissing cockroaches are popular, but they also host potent mold ...

Their gentle nature, large size, odd sounds and low-maintenance care have made Madagascar hissing cockroaches popular educational tools and pets for years.

But the giant insects also have one unfortunate characteristic: Their hard bodies and feces are home to many mold species that could be triggering allergies in the kids and adults who handle the bugs, according to a new study.