title: The sex ratio at birth in South Africa increased 9months after the 2010 FIFA World Cup.
abstract: BACKGROUND
  In humans in the absence of significant stress the sex ratio at birth [males/(males+females)] is in favor of more male than female live births.
  
  
  METHODS
  This study sought to determine the influence of the 2010 Fédération Internationale de Football Association (FIFA) World Cup in South Africa on the sex ratio at birth in that country specifically 9months afterwards. Publicly available data from Statistics South Africa was utilized detailing recorded live births. Analysis was carried out by Chi-squared tests.
  
  
  RESULTS
  February and March 2011 about 9months after the World Cup, had the highest observed sex ratio at birth (relatively more male births) of 0.5063 for the period 2003 to 2012. The observed sex ratio at birth in the considered two months of 2011 was 0.63% (p=0.02) greater than the sex ratio at birth for corresponding periods from 2008 to 2012. The increase noted in 2011 corresponds to more than 1000 extra male births than expected for February and March 2011.
  
  
  CONCLUSIONS
  The 2010 FIFA World Cup was followed about 9months afterwards by a significant increase in the sex ratio at birth. The main mechanism driving the observed increase in the sex ratio at birth in South Africa is most likely more frequent sexual intercourse at population level during the tournament.
authors.affiliation: Gravida: National Centre for Growth & Development, University of Auckland, Auckland, New Zealand; Division of Epidemiology and Biostatistics, School of Public Health, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa; Irish Centre for Fetal and Neonatal Translational Research (INFANT), Department of Obstetrics and Gynaecology, University College Cork, Cork, Ireland. Electronic address: parturitions@gmail.com.
authors.forename: Gwinyai
authors.initials: G
authors.lastname: Masukume
authors.affiliation: Academic Department of Paediatrics, Medical School, Mater Dei Hospital, Malta. Electronic address: victor.e.grech@gov.mt.
authors.forename: Victor
authors.initials: V
authors.lastname: Grech
mesh_terms: D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D036801:Parturition; D012744:Sex Ratio; D012916:Soccer; D013019:South Africa
keywords: Female; Male; Population stress; Pregnancy; Sex ratio; South Africa; World Cup