title: Atomic bomb testing and its effects on global male to female ratios at birth.
abstract: OBJECTIVE
  Fallout from atomic bomb testing may travel great distances before precipitating. Males are born in excess of females in a ratio that approximates 0.515 (M/T: male live births divided by total live births. Radiation increases M/T by causing lethal malformations that affect female more than male foetuses, decreasing total births. This study was carried out in order to ascertain whether the effects of increased background radiation levels from atomic weapon testing had any widespread effects on M/T and births in the Americas, Europe, Asia and Australasia in relation to the Partial Test Ban Treaty of 1963.
  
  
  METHODS
  Annual live births by gender were obtained from a World Health Organization dataset and annual number of atomic bomb tests were also obtained (historical data).
  
  
  RESULTS
  Overall, 94.5% of births studied showed a uniform reduction in M/T between the early 1950s to the late 1960s, followed by an increase to the mid-1970s, with a subsequent decline. A negative correlation of M/T with total births was found in 66% of births studied, and these were the regions which exhibited the rising M/T pattern in the 1970s. The birth deficit for countries with significant correlations of total births with M/T (North America, Europe and Asia) was estimated at 10090701.
  
  
  CONCLUSIONS
  A rising M/T was found in most regions in temporal association with atomic weapon testing. Most of these regions also had an associated decline in total births. Elevated levels of man-made ambient radiation may have reduced total births, affecting pregnancies carrying female pregnancies more than those carrying male pregnancies, thereby skewing M/T toward a higher male proportion.
authors.affiliation: Department of Paediatrics, Mater Dei Hospital, Malta.
authors.forename: Victor
authors.initials: V
authors.lastname: Grech
mesh_terms: D005260:Female; D006801:Humans; D008297:Male; D054043:Nuclear Weapons; D000069079:Radiation Exposure / Q000706:statistics & numerical data*; D012744:Sex Ratio; D014944:World Health Organization
keywords: Birth Rate/*trends; infant; ionizing; newborn; radiation; sex ratio