Variations in male-female infant ratios among births to Canadian- and Indian-born mothers, 1990-2011: a population-based register study
Bibliographic record
Abstract
BACKGROUND: We assessed variations in the male-female infant ratios among births to Canadian-born and Indian-born mothers according to year of birth, province and country of birth of each parent. METHODS: In this population-based register study, we analyzed birth certificates of 5 853 970 singleton live births to Canadian-born and 177 990 singleton live births to Indian-born mothers giving birth in Canada from 1990 to 2011. Male-female ratios were stratified by live birth order and plotted by year of birth. Logistic regression was used to assess whether ratios varied between Canadian provinces and according to the birthplace of each parent. The deficit in the number of girls was estimated using bootstrap methods. RESULTS: Among Canadian-born mothers, male-female ratios were about 1.05, with negligible fluctuations by birth order, year and province. Among Indian-born mothers, the overall male-female ratio at the third birth was 1.38 (95% confidence interval [CI] 1.34-1.41) and was 1.66 (95% CI 1.56-1.76) at the fourth or higher-order births. There was little variability in the ratios between provinces. Couples involving at least 1 Indian-born parent had higher than expected male-female ratios at the second and higher-order births, particularly when the father was Indian-born. The deficit in the expected number of girls among Indian immigrants to Canada in the study period was estimated to be 4472 (95% CI 3211-5921). INTERPRETATION: Fewer than expected girls at the third and higher-order births have been born to Indian immigrants across Canada since 1990. This trend was also seen among couples of mixed nativity, including those involving a Canadian-born mother and an Indian-born father. Fathers should be considered when investigating sex ratios at birth.
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How this classification was reachedexpand
Direct model labels (unvalidated)
Per-model category and study-design labels from the labeling rounds. They are machine output, unvalidated, and the disagreement between models ships as data. No study design here is MEDLINE-validated yet.
| Model arm | Categories | Study design | Confidence |
|---|---|---|---|
| gemma | no category Domain: not available · Genre: Empirical About the Canadian research system: no · About a Canadian topic: yes | Observational | low |
| gpt | no category Domain: not available · Genre: Empirical About the Canadian research system: no · About a Canadian topic: yes | Observational | low |
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedLabeled directly by 2 models reading the full record.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".