Mid 19th century (in an earlier sense). In sense 1 perhaps from scientific Latin monogeneus + -ous; compare French monogéné. In sense 2 from mono- + -geneous, after French monogène.
Definition of monogeneous in US English:
monogeneous
adjectiveˌmɒnə(ʊ)ˈdʒiːnɪəs
Mathematics= "monogenic".
Origin
Mid 19th century (in an earlier sense). In sense 1 perhaps from scientific Latin monogeneus + -ous; compare French monogéné. In sense 2 from mono- + -geneous, after French monogène.