Lists of sex linked diseases. Colored scanning electron micrograph SEM of Blattella germanica, the German cockroach, one of the smallest known species. Franklin D. Your contribution may be further edited by our staff, and its publication is subject to our final approval. Syphilis This sexually transmitted disease first appeared in Italy in A colored scanning electron micrograph close-up of Periplaneta americanathe American cockroach, which can be found around the world. Please try again later. See More Recent Categories Archives. This can lead to bone problems, bowed legs, and stunted growth. They may find their relationships unfulfilling, and others may not enjoy being around them.