Does the month you were born in determine whether you’re right handed, ’’t mean it applies universally, and it definitely doesn’t mean the one is necessarily causing the other. You are not defined by your birthday. This film is part of our new series that will provide the blueprint for a scientifically perfect summer. From sweating to hay fever, insects to jet lag, Kate Mulcahy will help you hack summer to engineer the perfect season. Taking a different topic each Thursday, the videos will gradually build up an equation for summer perfection; a summer survival guide certified by science. Subscribe to keep up each week: http://bit.ly/RiSubscRibe References: Riala, K. et al. (2009) Season of birth and smoking: findings from the northern Finland 1966 birth cohort. Chronobiology International 26(8): 1660-1672 doi: http://dx.doi.org/10.3109/07420520903534484 Marzulo, G. and Clarke Fraser, F. (2009) Conception season and cerebral asymmetries among American baseball players: Implications for the seasonal birth effect in schizophrenia. Psychiatry Research 167(3): 287-293 doi: http://dx.doi.org/10.1016/j.psychres.2008.02.002 Mandel, Y. et al. (2008) Season of birth, natural light, and myopia. Ophthalmology 115(4): 686-692 doi: http://dx.doi.org/10.1016/j.ophtha.2007.05.040 Davies. G. et al. (2003) A systematic review and meta-analysis of Northern Hemisphere season of birth studies in schizophrenia. Schizophrenia Bulletin 29 (3): 587-593 doi: http://dx.doi.org/10.1093/oxfordjournals.schbul.a007030 The Ri is on Twitter: http://twitter.com/ri_science and Facebook: http://www.facebook.com/royalinstitution and Tumblr: http://ri-science.tumblr.com/ Our editorial policy: http://www.rigb.org/home/editorial-policy Subscribe for the latest science videos: http://bit.ly/RiNewsletter