ArticleProceedings of the National Academy of Sciences of the United States of America2015
The human sex ratio from conception to birth.
Article in Proceedings of the National Academy of Sciences of the United States of America, 2015. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 106 papers, 4 of them syntheses that pooled it.
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Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
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Who cites it
106 citing papers in PubMed, 4 syntheses or guidelines pooled it.
- The influence of fetal sex on maternal blood pressure in pregnancy.BMC medicine · 2025Pooled it
- Sex differences in the effects of prematurity and/or low birthweight on neurodevelopmental outcomes: systematic review and meta-analyses.Biology of sex differences · 2023Pooled it
- Fetal sex and maternal pregnancy outcomes: a systematic review and meta-analysis.Biology of sex differences · 2020Pooled it
- Fetal sex-specific differences in gestational age at delivery in pre-eclampsia: a meta-analysis.International journal of epidemiology · 2017Pooled it
- The Role of Maternal Preconception Adiposity in Human Offspring Sex and Sex Ratio.American journal of epidemiology · 2023Trial
- Sex ratio following preconception low-dose aspirin in women with prior pregnancy loss.The Journal of clinical investigation · 2015Trial
- Vanishing Twin Syndrome After In Vitro Fertilization and Embryo Transfer: Mechanisms, Perinatal Consequences, Diagnostic Pitfalls, and Prevention.Biomedicines · 2026Review
- Preconception Blood Pressure and Sex of the Baby: A Large Prospective Cohort Study in China.Journal of clinical hypertension (Greenwich, Conn.) · 2026Article
- The decade of double-trouble: live birth and stillbirth sex ratio variation in Finland during the COVID-19 pandemic and Russia's attack on Ukraine.European journal of epidemiology · 2026Article
- Trophoblast stem cells and syncytiotrophoblasts lack inflammatory responses to LPS but retain robust interferon-mediated antiviral immunity.Reproduction & fertility · 2026Article
- Lim Homeobox 8 Is Essential for Beta Adrenergic Stimulation of Thermogenesis in Human Adipocytes.Cells · 2026Article
- Temperature and sex ratios at birth.Proceedings of the National Academy of Sciences of the United States of America · 2026Article
- Prenatal Assessment of Fetal Vertebrae and Ribs by Three-Dimensional Ultrasound and the Association with Fetal and Neonatal Outcome.Fetal diagnosis and therapy · 2026Article
- Maternal serum progesterone and BMI are associated with neonatal sex ratios following single frozen embryo transfer.PloS one · 2026Article
- Toll-like receptors 7 and 8 can be targeted to enrich Y-chromosome sperm in the domestic dog.Reproduction & fertility · 2026Article
- Article
- The association of embryo developmental rate and morphological grading with neonatal sex ratio.Scientific reports · 2025Article
- The Effect of Assisted Reproductive Technologies on Human Sex Ratios.The Australian & New Zealand journal of obstetrics & gynaecology · 2025Article
- Is sex at birth a biological coin toss? Insights from a longitudinal and GWAS analysis.Science advances · 2025Article
- Unveiling the Effects of Natural Disasters and Nuclear Energy on the Secondary Sex Ratio: A Comprehensive Review.Life (Basel, Switzerland) · 2025Review
46 more citing papers are in PubMed but not listed here.
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8 authors.
Funding
Abstract
We describe the trajectory of the human sex ratio from conception to birth by analyzing data from (i) 3- to 6-d-old embryos, (ii) induced abortions, (iii) chorionic villus sampling, (iv) amniocentesis, and (v) fetal deaths and live births. Our dataset is the most comprehensive and largest ever assembled to estimate the sex ratio at conception and the sex ratio trajectory and is the first, to our knowledge, to include all of these types of data. Our estimate of the sex ratio at conception is 0.5 (proportion male), which contradicts the common claim that the sex ratio at conception is male-biased. The sex ratio among abnormal embryos is male-biased, and the sex ratio among normal embryos is female-biased. These biases are associated with the abnormal/normal state of the sex chromosomes and of chromosomes 15 and 17. The sex ratio may decrease in the first week or so after conception (due to excess male mortality); it then increases for at least 10-15 wk (due to excess female mortality), levels off after ∼20 wk, and declines slowly from 28 to 35 wk (due to excess male mortality). Total female mortality during pregnancy exceeds total male mortality. The unbiased sex ratio at conception, the increase in the sex ratio during the first trimester, and total mortality during pregnancy being greater for females are fundamental insights into early human development.
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