2014-09-04

[public] 8.57M views, 134K likes, dislikes audio only

MinuteEarth

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

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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

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Elephant Seal 1

Photo by: Roy Mangersnes

http://roywildphoto.blogspot.com/2008/11/elephant-seals.html

Elephant Seal 2

Photo by: Mike Baird

https://www.flickr.com/photos/mikebaird/11830159673/

White tailed deer

Photo by: Public Domain

http://en.wikipedia.org/wiki/File:White-tailed_deer.jpg

Key Deer

Photo by: IanarÈ SÈvi

http://commons.wikimedia.org/wiki/File:Odocoileus_virginianus_clavium_fawn.jpg

Male Lion

Photo by: Wikimedia user Robek

http://commons.wikimedia.org/wiki/File:Pair_of_lions_v2.jpg

Baby Lion

Photo by: Flickr user fortherock

https://www.flickr.com/photos/fortherock/3897872187/

Brad Pitt

Photo by: Foreign and Commonwealth Office

http://www.flickr.com/photos/foreignoffice/14217374639/

Kids

Photo by: Barbara Hobbs

http://commons.wikimedia.org/wiki/File:Upclose_of_kids_-_Alberti_Flea_Circus,_MerleFest_2013.jpg

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REFERENCES

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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.org/content/271/1549/1723

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/10.1080/19485565.1988.9988703?journalCode=hsbi20#.U-5oSPldWRM

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/10.2307/1971953?uid=3739824&uid=2&uid=4&uid=3739256&sid=21104121507601

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_1_publications/C/Clutton-Brock_et_al_1986_Dominance_breeding_success_and_offspring_sex_ratios_in_red_deer.pdf

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-publications/publications/other-publications/monographs/m-li01-1-toc.aspx

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%3Adoi%2F10.1371%2Fjournal.pone.0057446

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.org/content/early/2012/03/16/rspb.2012.0320.full

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%3Adoi%2F10.1371%2Fjournal.pone.0067867

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/179/4068/90.abstract