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Created by Henry Reich
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Music by Nathaniel Schroeder:   / drschroeder  
Narrated by: Emily Elert
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References

Cameron, E.Z. (2004). Facultative adjustment of mammalian sex ratios in support of the TriversWillard 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): 517523.http://www.jstor.org/discover/10.2307...

CluttonBrock, 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: 460471. 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/newsandpublicat...

Schnettler, S. (2013). Revisiting a Sample of U.S. Billionaires: How Sample Selection and Timing of Maternal Condition Influence Findings on the TriversWillard 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):28832890. 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: 9092. http://www.sciencemag.org/content/179...


Photo 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...