ArticleProceedings of the National Academy of Sciences of the United States of America2025
Parental mixed-gender preferences revealed by IVF twin births.
Article in Proceedings of the National Academy of Sciences of the United States of America, 2025. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 1 paper.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
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Who cites it
1 citing paper in PubMed.
- Parental mixed-gender preferences revealed by IVF twin births.Proceedings of the National Academy of Sciences of the United States of America · 2025Article
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Authors and funding
4 authors.
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Abstract
In vitro fertilization (IVF) affects human fertility by 1) increasing the probability of multiple births through the transfer of multiple embryos, 2) raising the proportion of dizygotic twins, which leads to a higher occurrence of one-boy-one-girl twins, and 3) enabling gender selection through preimplantation genetic screening (PGS) when parents have specific gender preferences. While the above-mentioned increase in multiple births is well documented, the impact on the twins' gender composition remains under-explored, partly because 2) and 3) are intertwined. This study uses millions of administrative observations from Taiwan to disentangle the effects of IVF on twin birth rates, gender composition, and parental preferences. Families are grouped by maternal age and family wealth across different periods, enabling a comparative analysis of socioeconomic and temporal factors. By examining the gender composition of first-born twins within these age-wealth-time groups, we can identify and test whether parents have gender preferences for one-boy-one-girl twins. Our empirical evidence reveals a significant increase in IVF adoption, particularly among older and wealthier mothers. The proportion of one-boy-one-girl twins among first-birth twins has risen from 20.42 to 41.86% over the past 30 y, and this proportion increases with wealth ranking, significantly exceeding expected ratios in the absence of gender preference. Parental gender preference contributed to approximately 10.95% of one-boy-one-girl twins among the wealthiest group, revealing a significant impact of parental preference on twin gender composition. These trends raise ethical and social concerns regarding reproductive technologies.
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