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Sex ratios at birth among second-generation mothers of South Asian ethnicity in Ontario, Canada: a retrospective population-based cohort study
  1. Susitha Wanigaratne1,2,
  2. Pamela Uppal3,
  3. Manvir Bhangoo4,
  4. Alia Januwalla5,
  5. Deepa Singal6,
  6. Marcelo L Urquia1,2,6
  1. 1 Centre for Urban Health Solutions, St. Michael’s Hospital, Toronto, Ontario, Canada
  2. 2 Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada
  3. 3 Ontario Non-Profit Network, Toronto, Ontario, Canada
  4. 4 Malton Neighborhood Services, Malton, Ontario, Canada
  5. 5 Knowledge Translation Program, St. Michael’s Hospital, Toronto, Ontario, Canada
  6. 6 Department of Community Health Sciences, Manitoba Centre for Health Policy, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
  1. Correspondence to Dr Susitha Wanigaratne, Centre for Urban Health Solutions, St. Michael’s Hospital, Toronto, ON M5B 1W8, Canada; wanigaratnes{at}


Background Son-biased sex ratios at birth (M:F), an extreme manifestation of son preference, are predominately found in East and South Asia. Studies have examined sex ratios among first-generation migrants from these regions, but few have examined second-generation descendants. Our objective was to determine whether son-biased sex ratios persist among second-generation mothers with South Asian ethnicity in Ontario, Canada.

Methodology A surname algorithm identified a population-based cohort of mothers with South Asian ethnicity who gave birth in Ontario between 1993 and 2014 (n=59 659). Linking to official immigration data identified births to first-generation mothers (ie, immigrants). Births not to immigrants were designated as being to second-generation mothers (ie, born in Canada) (n=10 273). Sex ratios and 95% CI were stratified by the sex of previous live births and by whether it was preceded by ≥1 abortion for both first-generation and second-generation mothers.

Results Among mothers with two previous daughters and at least one prior abortion since the second birth, both second-generation mothers and first-generation mothers had elevated sex ratios at the third birth (2.80 (95% CI 1.36 to 5.76) and 2.46 (95% CI 1.93 to 3.12), respectively). However, among mothers with no prior abortion, second-generation mothers had a normal sex ratio, while first-generation mothers gave birth to 142 boys for every 100 girls (95% CI 125 to 162 boys for every 100 girls).

Conclusion Son preference persists among second-generation mothers of South Asian ethnicity. Culturally sensitive and community-driven gender equity interventions are needed.

  • migration
  • ethnicity
  • public health
  • social epidemiology
  • perinatal epidemiology

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  • Contributors SW and MLU conceived the research question and designed the study. SW conducted statistical analysis, interpreted the results and wrote the first and subsequent drafts of the manuscript. PU, MB, AJ and DS contributed to data interpretation and revisions of the manuscript. MLU obtained funding. All authors approved the final version of the submitted manuscript.

  • Funding This study was funded by a grant from the Canadian Institutes of Health Research (CIHR). SW’s postdoctoral fellowship is supported by a grant from CIHR. MLU holds a Canada Research Chair in Applied Population Health from CIHR.

  • Disclaimer The opinions, results and conclusions reported in this article are those of the authors and are independent from the funding sources. No endorsement by the Institute for Clinical Evaluative Sciences or the Ontario Ministry of Long-Term Care is intended or should be inferred. Parts of this material are based on data and information compiled and provided by the Canadian Institute of Health Information. However, the analyses, conclusions, opinions and statements expressed herein are those of the authors and not necessarily those of the Canadian Institute for Health Information. PU was employed at the Ontario Non-Profit Network (ONN) at the time this paper was written; however, her contribution to this paper is not related to her role at the ONN and therefore the results, conclusions and opinions expressed are not those of the ONN.

  • Patient consent Not required.

  • Ethics approval This study was approved by the institutional review board at Sunnybrook Health Sciences Centre and the Research Ethics Board at St. Michael’s Hospital, Toronto, Canada.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement There are no additional unpublished data from this study available.

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