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. 2001 Jul;109(7):749–752. doi: 10.1289/ehp.01109749

The secular trends in male:female ratio at birth in postwar industrialized countries.

P H Jongbloet 1, G A Zielhuis 1, H M Groenewoud 1, P C Pasker-De Jong 1
PMCID: PMC1240380  PMID: 11485875

Abstract

Finnish investigators [Vartiainen et al. Environmental Chemicals and Changes in Sex Ratio: Analysis Over 250 Years in Finland. Environ Health Perspect 107:813-815 (1999)] presented the sex ratio of all newborn babies from 1751 to 1997 in order to evaluate whether Finnish long-term data are compatible with the hypothesis that the decrease in the ratio of male to female births after World War I and World War II in industrial countries is caused by environmental factors. They found an increase in the proportion of males from 1751 to 1920, which was interrupted by peaks in male births during World War I and World War II and followed by a decrease thereafter, similar to the trends in many other countries. The turning point of male proportion, however, preceded the period of industrialization and introduction of pesticides and hormonal drugs. Thus, a causal association between these environmental exposures and this decrease is unlikely. In addition, none of the various family parameters (e.g., paternal age, maternal age, age difference in parents, birth order) could explain the historical time trends. Vartiainen et al. concluded that at present it is unknown how these historical trends could be mediated. The postwar secular decline of the male:female ratio at birth is not an isolated phenomenon and parallels the decline of perinatal morbidity and mortality, congenital anomalies, and various constitutional diseases. This parallelism indicates a common etiology and may be caused by reduction of conceptopathology, as a correlate to increasing socioeconomic development. An inverted dose response or the dose-response fallacy due to vanishing male conceptuses explains the low sex ratios before World War I and World War II in newborns from black parents and from the lowest socioeconomic classes.

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Selected References

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  1. Abramowicz M., Barnett H. L. Sex ratio of infant mortality. Am J Dis Child. 1970 Apr;119(4):314–315. doi: 10.1001/archpedi.1970.02100050316005. [DOI] [PubMed] [Google Scholar]
  2. Astolfi P., Zonta L. A. Reduced male births in major Italian cities. Hum Reprod. 1999 Dec;14(12):3116–3119. doi: 10.1093/humrep/14.12.3116. [DOI] [PubMed] [Google Scholar]
  3. Broer K. H., Winkhaus I., Sombroek H., Kaiser R. Frequency of Y-chromatin bearing spermatozoa in intracervical and intrauterine postcoital tests. Int J Fertil. 1976;21(3):181–185. [PubMed] [Google Scholar]
  4. Brown A. S., Susser E. S. Sex differences in prevalence of congenital neural defects after periconceptional famine exposure. Epidemiology. 1997 Jan;8(1):55–58. doi: 10.1097/00001648-199701000-00009. [DOI] [PubMed] [Google Scholar]
  5. Clutton-Brock T. H., Iason G. R. Sex ratio variation in mammals. Q Rev Biol. 1986 Sep;61(3):339–374. doi: 10.1086/415033. [DOI] [PubMed] [Google Scholar]
  6. Cruz-Coke R. Letter: Birth control and genetic changes in Chile. Lancet. 1976 Mar 13;1(7959):591–592. doi: 10.1016/s0140-6736(76)90394-9. [DOI] [PubMed] [Google Scholar]
  7. Cui K. H. Size differences between human X and Y spermatozoa and prefertilization diagnosis. Mol Hum Reprod. 1997 Jan;3(1):61–67. doi: 10.1093/molehr/3.1.61. [DOI] [PubMed] [Google Scholar]
  8. Davis D. L., Gottlieb M. B., Stampnitzky J. R. Reduced ratio of male to female births in several industrial countries: a sentinel health indicator? JAMA. 1998 Apr 1;279(13):1018–1023. doi: 10.1001/jama.279.13.1018. [DOI] [PubMed] [Google Scholar]
  9. Guerrero R., Lanctot C. A. Aging of fertilizing gametes and spontaneous abortion. Effect of the day of ovulation and the time of insemination. Am J Obstet Gynecol. 1970 May 15;107(2):263–267. doi: 10.1016/0002-9378(70)90595-8. [DOI] [PubMed] [Google Scholar]
  10. Harlow S. D., Ephross S. A. Epidemiology of menstruation and its relevance to women's health. Epidemiol Rev. 1995;17(2):265–286. doi: 10.1093/oxfordjournals.epirev.a036193. [DOI] [PubMed] [Google Scholar]
  11. Harlow S. D., Matanoski G. M. The association between weight, physical activity, and stress and variation in the length of the menstrual cycle. Am J Epidemiol. 1991 Jan;133(1):38–49. doi: 10.1093/oxfordjournals.aje.a115800. [DOI] [PubMed] [Google Scholar]
  12. Hellerstedt W. L., Pirie P. L., Lando H. A., Curry S. J., McBride C. M., Grothaus L. C., Nelson J. C. Differences in preconceptional and prenatal behaviors in women with intended and unintended pregnancies. Am J Public Health. 1998 Apr;88(4):663–666. doi: 10.2105/ajph.88.4.663. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Hobbs C. A., Sherman S. L., Yi P., Hopkins S. E., Torfs C. P., Hine R. J., Pogribna M., Rozen R., James S. J. Polymorphisms in genes involved in folate metabolism as maternal risk factors for Down syndrome. Am J Hum Genet. 2000 Aug 7;67(3):623–630. doi: 10.1086/303055. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Hytten F. E. Boys and girls. Br J Obstet Gynaecol. 1982 Feb;89(2):97–99. doi: 10.1111/j.1471-0528.1982.tb04672.x. [DOI] [PubMed] [Google Scholar]
  15. James W. H. Evidence that mammalian sex ratios at birth are partially controlled by parental hormone levels at the time of conception. J Theor Biol. 1996 Jun 21;180(4):271–286. doi: 10.1006/jtbi.1996.0102. [DOI] [PubMed] [Google Scholar]
  16. Jejeebhoy S. J. Evidence of increasing natural fertility in Taiwan. Soc Biol. 1983 Winter;30(4):388–399. doi: 10.1080/19485565.1983.9988552. [DOI] [PubMed] [Google Scholar]
  17. Jongbloet P. H., Zielhuis G. A., Pasker-de Jong P. C. Interval between pregnancies and risk of spontaneous abortions. Epidemiology. 2000 Nov;11(6):738–739. doi: 10.1097/00001648-200011000-00026. [DOI] [PubMed] [Google Scholar]
  18. Khoury M. J., Flanders W. D., James L. M., Erickson J. D. Human teratogens, prenatal mortality, and selection bias. Am J Epidemiol. 1989 Aug;130(2):361–370. doi: 10.1093/oxfordjournals.aje.a115342. [DOI] [PubMed] [Google Scholar]
  19. Khoury M. J., James L. M., Flanders W. D., Erickson J. D. Interpretation of recurring weak associations obtained from epidemiologic studies of suspected human teratogens. Teratology. 1992 Jul;46(1):69–77. doi: 10.1002/tera.1420460110. [DOI] [PubMed] [Google Scholar]
  20. Källén B., Cocchi G., Knudsen L. B., Castilla E. E., Robert E., Daltveit A. K., Lancaster P. L., Mastroiacovo P. International study of sex ratio and twinning of neural tube defects. Teratology. 1994 Nov;50(5):322–331. doi: 10.1002/tera.1420500503. [DOI] [PubMed] [Google Scholar]
  21. Lam P. K., Torfs C. P., Brand R. J. A low pregnancy body mass index is a risk factor for an offspring with gastroschisis. Epidemiology. 1999 Nov;10(6):717–721. [PubMed] [Google Scholar]
  22. Marcus M., Kiely J., Xu F., McGeehin M., Jackson R., Sinks T. Changing sex ratio in the United States, 1969-1995. Fertil Steril. 1998 Aug;70(2):270–273. doi: 10.1016/s0015-0282(98)00149-6. [DOI] [PubMed] [Google Scholar]
  23. Mattheij J. A., Swarts J. J., Hurks H. M., Mulder K. Advancement of meiotic resumption in graafian follicles by LH in relation to preovulatory ageing of rat oocytes. J Reprod Fertil. 1994 Jan;100(1):65–70. doi: 10.1530/jrf.0.1000065. [DOI] [PubMed] [Google Scholar]
  24. Mikamo K. Intrafollicular overripeness and teratologic development. Cytogenetics. 1968;7(3):212–233. doi: 10.1159/000129985. [DOI] [PubMed] [Google Scholar]
  25. Mizuno R. The male/female ratio of fetal deaths and births in Japan. Lancet. 2000 Aug 26;356(9231):738–739. doi: 10.1016/S0140-6736(00)02637-4. [DOI] [PubMed] [Google Scholar]
  26. Mocarelli P., Gerthoux P. M., Ferrari E., Patterson D. G., Jr, Kieszak S. M., Brambilla P., Vincoli N., Signorini S., Tramacere P., Carreri V. Paternal concentrations of dioxin and sex ratio of offspring. Lancet. 2000 May 27;355(9218):1858–1863. doi: 10.1016/S0140-6736(00)02290-X. [DOI] [PubMed] [Google Scholar]
  27. Møller H. Change in male:female ratio among newborn infants in Denmark. Lancet. 1996 Sep 21;348(9030):828–829. doi: 10.1016/S0140-6736(05)65253-1. [DOI] [PubMed] [Google Scholar]
  28. Münster K., Schmidt L., Helm P. Length and variation in the menstrual cycle--a cross-sectional study from a Danish county. Br J Obstet Gynaecol. 1992 May;99(5):422–429. doi: 10.1111/j.1471-0528.1992.tb13762.x. [DOI] [PubMed] [Google Scholar]
  29. Parazzini F., La Vecchia C., Levi F., Franceschi S. Trends in male:female ratio among newborn infants in 29 countries from five continents. Hum Reprod. 1998 May;13(5):1394–1396. doi: 10.1093/humrep/13.5.1394. [DOI] [PubMed] [Google Scholar]
  30. Peltonen M., Rosén M., Lundberg V., Asplund K. Social patterning of myocardial infarction and stroke in Sweden: incidence and survival. Am J Epidemiol. 2000 Feb 1;151(3):283–292. doi: 10.1093/oxfordjournals.aje.a010204. [DOI] [PubMed] [Google Scholar]
  31. Pierce J. P., Fiore M. C., Novotny T. E., Hatziandreu E. J., Davis R. M. Trends in cigarette smoking in the United States. Educational differences are increasing. JAMA. 1989 Jan 6;261(1):56–60. [PubMed] [Google Scholar]
  32. Power C., Matthews S. Origins of health inequalities in a national population sample. Lancet. 1997 Nov 29;350(9091):1584–1589. doi: 10.1016/S0140-6736(97)07474-6. [DOI] [PubMed] [Google Scholar]
  33. Roseboom T. J., van der Meulen J. H., Osmond C., Barker D. J., Ravelli A. C., Schroeder-Tanka J. M., van Montfrans G. A., Michels R. P., Bleker O. P. Coronary heart disease after prenatal exposure to the Dutch famine, 1944-45. Heart. 2000 Dec;84(6):595–598. doi: 10.1136/heart.84.6.595. [DOI] [PMC free article] [PubMed] [Google Scholar]
  34. Rostron J., James W. H. Maternal age, parity, social class and sex ratio. Ann Hum Genet. 1977 Oct;41(2):205–217. doi: 10.1111/j.1469-1809.1977.tb01916.x. [DOI] [PubMed] [Google Scholar]
  35. Sarlio-Lähteenkorva S., Lahelma E. The association of body mass index with social and economic disadvantage in women and men. Int J Epidemiol. 1999 Jun;28(3):445–449. doi: 10.1093/ije/28.3.445. [DOI] [PubMed] [Google Scholar]
  36. Schramm R. D., Bavister B. D. A macaque model for studying mechanisms controlling oocyte development and maturation in human and non-human primates. Hum Reprod. 1999 Oct;14(10):2544–2555. doi: 10.1093/humrep/14.10.2544. [DOI] [PubMed] [Google Scholar]
  37. Selevan S. G., Lemasters G. K. The dose-response fallacy in human reproductive studies of toxic exposures. J Occup Med. 1987 May;29(5):451–454. [PubMed] [Google Scholar]
  38. Seller M. J. Sex, neural tube defects, and multisite closure of the human neural tube. Am J Med Genet. 1995 Sep 25;58(4):332–336. doi: 10.1002/ajmg.1320580406. [DOI] [PubMed] [Google Scholar]
  39. Shaver E. L., Carr D. H. The chromosome complement of rabbit blastocysts in relation to the time of mating and ovulation. Can J Genet Cytol. 1969 Jun;11(2):287–293. doi: 10.1139/g69-036. [DOI] [PubMed] [Google Scholar]
  40. Smith D. W. Is greater female longevity a general finding among animals? Biol Rev Camb Philos Soc. 1989 Feb;64(1):1–12. doi: 10.1111/j.1469-185x.1989.tb00635.x. [DOI] [PubMed] [Google Scholar]
  41. Susser E., Hoek H. W., Brown A. Neurodevelopmental disorders after prenatal famine: The story of the Dutch Famine Study. Am J Epidemiol. 1998 Feb 1;147(3):213–216. doi: 10.1093/oxfordjournals.aje.a009439. [DOI] [PubMed] [Google Scholar]
  42. Teitelbaum M. S., Mantel N. Socio-economic factors and the sex ratio at birth. J Biosoc Sci. 1971 Jan;3(1):23–41. doi: 10.1017/s0021932000007793. [DOI] [PubMed] [Google Scholar]
  43. Vartiainen T., Kartovaara L., Tuomisto J. Environmental chemicals and changes in sex ratio: analysis over 250 years in finland. Environ Health Perspect. 1999 Oct;107(10):813–815. doi: 10.1289/ehp.99107813. [DOI] [PMC free article] [PubMed] [Google Scholar]
  44. WITSCHI E. Overripeness of the egg as a cause of twinning and teratogenesis: a review. Cancer Res. 1952 Nov;12(11):763–786. [PubMed] [Google Scholar]
  45. Weinberg C. R., Baird D. D., Wilcox A. J. The sex of the baby may be related to the length of the follicular phase in the conception cycle. Hum Reprod. 1995 Feb;10(2):304–307. doi: 10.1093/oxfordjournals.humrep.a135932. [DOI] [PubMed] [Google Scholar]
  46. Williams R. J., Gloster S. P. Human sex ratio as it relates to caloric availability. Soc Biol. 1992 Fall-Winter;39(3-4):285–291. doi: 10.1080/19485565.1992.9988823. [DOI] [PubMed] [Google Scholar]
  47. van den Broek J. M. Change in male proportion among newborn infants. Lancet. 1997 Mar 15;349(9054):805–805. doi: 10.1016/S0140-6736(05)60234-6. [DOI] [PubMed] [Google Scholar]

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