title: Why the twinning rate is higher in Africa than elsewhere: an analysis of selected factors.
abstract: OBJECTIVE
  To examine the rate of spontaneous twinning in selected countries in order to evaluate the impact of environmental stress and related socioeconomic factors on balancing reproductive activity and longevity.
  
  
  METHODS
  Four countries with similar ancestry were considered, 2 in Africa and 2 in the Caribbean. Data on gross domestic product per capita, as a measure of indigenous conditions, access to proper diet, health care, sanitation and shelter were compared with the relative rate of twinning.
  
  
  RESULTS
  The data show an inverse relationship between wealth and environmental conditions, and the incidence of multiple gestations.
  
  
  CONCLUSIONS
  Through goods and services, improved living conditions reduce environmental stress and its adverse effect on the balance of biologic reproduction vs. longevity. In addition, breast-feeding, as a social expression and an economic easement, correlates with the chance of conceiving twins in a subsequent pregnancy. It would thus appear that the twinning rate can be taken as a barometer of the population's biologic attempt to perpetuate its gene pool expeditiously when an existential threat occurs.
authors.affiliation: Department of Biochemistry, International American University School of Medicine, St. Lucia, West Indies. dav4601@aol.com
authors.forename: Gary
authors.initials: G
authors.lastname: Steinman
mesh_terms: D001723:Birth Rate; D001942:Breast Feeding; D004467:Economics; D004522:Educational Status; D005260:Female; D005869:Ghana; D005102:Health Expenditures; D006801:Humans; D008017:Life Expectancy; D009549:Nigeria; D011159:Population Surveillance; D011247:Pregnancy; D019437:Saint Kitts and Nevis; D019431:Saint Lucia; D012499:Sanitation; D012924:Social Conditions; D014427:Twins