Aim Along with changes to the human physique recorded over the past decades in certain countries, there are also changes concerning the male-female birth ratio. The aim of this study was to establish the movement of male-female birth ratios and factors affecting the ratio. Methods This retrospective study was conducted in Zagreb, Croatia, in the period from 1985 to 2019 on a sample of 3804 newborns. Results In the 35-year period the ratio of boys and girls at birth did not change significantly. Girls had lower birth weight, and boys had higher birth length. In the war period (1992-1994), a mild increase in the ratio of boys was noted, but not statistically significant. Father’s age in the last period examined (2007-2009) showed to be a statistically significant predictor of the child’s gender. Namely, the descendants of younger fathers were statistically significantly more frequently girls, while the descendants of older fathers were more frequently boys. Married mothers had higher percentage of male births (51.5%), and a lower percentage (47.1%) by unmarried mothers. Conclusion The changes in birth ratios are particularly pronounced in different age and socioeconomic groups of parents nowadays when the growth of living standards is accompanied by significant changes of the human physique.
Vranes H, Gall V, Jukić M, Vranes Z. Secular changes in growth and obesity in perinatal population. Coll Antropol. 2012. p. 549–54.
2.
Juresa V, Musil V, Tiljak M. Growth charts for Croatian school children and secular trends in past twenty years. Coll Antropol. 2012. p. 47–57.
3.
Toselli S, Ventrella A, Brasili P. Prevalence and tracking of weight disorders in Italian primary school students: a three-year follow-up. Coll Antropol. 2012. p. 63–7.
4.
Mikulan R, Piko B. High school students’ body weight control: differences between athletes and non-athletes. Coll Antropol. 2012. p. 79–86.
5.
Parízková J. The role of motor and nutritional individuality in childhood obesity. Coll Antropol. 2012. p. 23–9.
6.
Stévant I, Nef S. Genetic control of gonadal sex determination and development. Trends Genet. 2019. p. 346–58.
7.
Allan B, Brant R, Seidel J, Jarrell J. Declining sex ratios in Canada. CMAJ. 1997. p. 37–41.
8.
Martuzzi M, Tanno D, Bertollini N, R. Declining trends of male proportion at birth in Europe. Arch Environ Health. 2001. p. 358–64.
9.
Grech V. Evidence of socio-economic stress and female foeticide in racial disparities in the gender ratio at birth in the United States. Early Hum Dev. 1995. p. 63–5.
10.
Nicolich M, Huebner W, Schnatter A. Influence of parental and biological factors on the male birth fraction in the United States: an analysis of birth certificate data from 1964 through 1988. Fertil Steril. 2000. p. 487–92.
11.
James W. Hormonal control of sex ratio. J Theor Biol. 1986. p. 427–41.
12.
Venero Fernández S, Medina R, Britton J, Fogarty A. The association between living through a prolonged economic depression and the male:female birth ratio--a longitudinal study from Cuba, 1960-2008. Am J Epidemiol. 2011. p. 1327–31.
13.
Smith D, Behren V, J. Trends in the sex ratio of California births, 1960-1996. J Epidemiol Community Health. 2005. p. 1047–53.
14.
Ray J, Henry D, Urquia M. Sex ratios among Canadian liveborn infants of mothers from different countries. CMAJ. 2012. p. 492–6.
15.
Jongbloet P, Zielhuis G, Groenewoud H, Jong PD, P. The secular trends in male:female ratio at birth in postwar industrialized countries. Environ Health Perspect. 2001. p. 749–52.
16.
Strandskov H, Siemens G. An analysis of the sex ratios among single and plural births in the total, the white and the colored United States populations. Am J Phys Anthropol. 1946. p. 491–501.
17.
Machin G. Some causes of genotypic and phenotypic discordance in monozygotic twin pairs. Am J Med Genet. 1996. p. 216–28.
18.
Villamor E, Sparén P, Cnattingius S. Interpregnancy weight gain and the male-to-female sex ratio of the second pregnancy: a population-based cohort study. Fertil Steril. 2008. p. 1240–4.
19.
Davis D, Gottlieb M, Stampnitzky J. Reduced ratio of male to female births in several industrial countries: a sentinel health indicator? JAMA. 1998. p. 1018–23.
20.
Jargin S. Male to female ratio at birth: the role of background radiation vs. other factors. J Environ Stud. 2018. p. 4.
21.
James W, Grech V. Offspring sex ratio: Coital rates and other potential causal mechanisms. Early Human Development. 2018. p. 24–7.
22.
Polasek O. Did the 1991-1995 wars in the former Yugoslavia affect sex ratio at birth? Eur J Epidemiol. 2006. p. 61–4.
23.
James W. The variations of human sex ratio at birth during and after wars, and their potential explanations. J Theor Biol. 2009. p. 116–23.
24.
Chahnazarian A. Determinants of the sex ratio at birth: review of recent literature. Soc Biol. 1988. p. 214–35.
25.
Gutiérrez-Adán A, Pintado B, De La Fuente J. Demographic and behavioral determinants of the reduction of male-to-female birth ratio in Spain from 1981 to 1997. Hum Biol. 2000. p. 891–8.
26.
Figà-Talamanca I, Carbone P, Lauria L, Spinelli A, Ulizzi L. Environmental factors and the proportion of males at birth in Italy. Arch Environ Health. 2003. p. 119–24.
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