For one, cockroaches don't lay eggs in the manner implied by the story. A pregnant roach carries her eggs in a hard capsule called an ootheca, in which they incubate intact until they're ready to hatch. Outside the ootheca the eggs can't survive at all, let alone flourish within a human body. You wouldn't find cockroach eggs strewn about or deposited on envelopes. There are the logical inconsistencies, too.
Infestation legends derive from and play on people's horror of insects.
She goes to her doctor, but he says that he can see nothing suspicious and that she should not worry. They're concocted from a nugget of truth, latent dread and a generous dose of imagination. It's hard to resist passing them along. On examining her, the doctor found a large spider lodged next to her eardrum. Schendel Pest Control.