Why Do We Have More Boys Than Girls?

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2014Sep 4

Most human parents-to-be assume that the sex of their child comes down to a flip of the chromosomal coin, with an equal chance of having a boy or girl. But in reality, the odds aren’t even -for every 100 girls born, the world gains about 106 baby boys. CREDITS ********* Created by Henry Reich Narrated by: Emily Elert Production and Writing Team: Alex Reich, Peter Reich, Emily Elert, Ever Salazar, Kate Yoshida, and Henry Reich Music by Nathaniel Schroeder OTHER CREDITS ***************** Elephant Seal 1 Photo by: Roy Mangersnes http://roywildphoto.blogspot.com/2008... Elephant Seal 2 Photo by: Mike Baird https://www.flickr.com/photos/mikebai... White tailed deer Photo by: Public Domain http://en.wikipedia.org/wiki/File:Whi... Key Deer Photo by: IanarÈ SÈvi http://commons.wikimedia.org/wiki/Fil... Male Lion Photo by: Wikimedia user Robek http://commons.wikimedia.org/wiki/Fil... Baby Lion Photo by: Flickr user fortherock https://www.flickr.com/photos/forther... Brad Pitt Photo by: Foreign and Commonwealth Office http://www.flickr.com/photos/foreigno... Kids Photo by: Barbara Hobbs http://commons.wikimedia.org/wiki/Fil... SUPPORT MINUTEEARTH ************************** If you like what we do, you can help us!:

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OUR LINKS ************ Youtube | / minuteearth TikTok | / minuteearth Twitter | / minuteearth Instagram | / minute_earth Facebook | / minuteearth Website | https://minuteearth.com Apple Podcasts| https://podcasts.apple.com/us/podcast... REFERENCES ************** Cameron, E.Z. (2004). Facultative adjustment of mammalian sex ratios in support of the Trivers-Willard hypothesis: evidence for a mechanism. Proceedings of the Royal Society of London Series B 271:1723–1728. http://rspb.royalsocietypublishing.or... Chahnazarian, A. (1988). Determinants of the sex ratio at birth: Review of recent literature. Social Biology 35 (3–4): 214–235. http://www.tandfonline.com/doi/abs/10... Coale, A.J. (1991). Excess female mortality and the balance of the sexes in the population: An estimate of the number of "missing females." Population and Development Review 17(3): 517-523.http://www.jstor.org/discover/10.2307... Clutton-Brock, T. H., Albon, S. D., and Guinness, F. E. (1986). Great expectations: dominance, breeding success and offspring sex ratios in red deer. Animal Behavior 34: 460-471. http://www.kora.ch/malme/05_library/5... Kalben B. (2000). Why men die younger: causes of mortality differences by sex. North American Actuarial Journal 4(4): 83–111. https://www.soa.org/news-and-publicat... Schnettler, S. (2013). Revisiting a Sample of U.S. Billionaires: How Sample Selection and Timing of Maternal Condition Influence Findings on the Trivers-Willard Effect. PLoS ONE 8(2): e57446. http://www.plosone.org/article/info%3... Song, S. (2012). Does famine influence sex ratio at birth? Evidence from the 1959–1961 Great Leap Forward Famine in China. Proceedings of the Royal Society B 279(1739):2883-2890. http://rspb.royalsocietypublishing.or... Thogerson C.M., Brady, C.M., Howard, R.D., Mason, G.J., Pajor, E.A., Vicino, G.A., and Garner, J.P. (2013) Winning the genetic lottery: biasing birth sex ratio results in more grandchildren. PLoS One 8(7):e67867. http://www.plosone.org/article/info%3... Trivers, R.L., and Willard, D.E. (1973). Natural selection of parental ability to vary the sex ratio of offspring. Science 179: 90-92. http://www.sciencemag.org/content/179...