monogeny

from The Century Dictionary.

• noun The ‘natal probability,’ or statistical expectation of offspring, based on the age of one parent only.
• noun Same as monogony, 1, or monogenesis.
• noun Same as monogenism.

from the GNU version of the Collaborative International Dictionary of English.

• noun Monogenesis.
• noun (Anthropol.) The doctrine that the members of the human race have all a common origin.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun monogenesis
• noun anthropology The doctrine that all of the members of the human race have a common origin.