Besides sperm what can cause a postive pregnancy test?

False positive test: "some diseases of the liver, cancers, and other medical conditions may produce elevated HCG and thus cause a false positive pregnancy test. These include choriocarcinoma and other germ cell tumors, IgA deficiencies, heterophile antibodies, enterocystoplasties, gestational trophoblastic diseases (gtd), and gestational trophoblastic neoplasms (gtn)." wikipedia.