Girls with twin brothers may be losing out in the womb, a new study from Edinburgh University has revealed. The research was carried out on a population wild sheep and their lambs, but the evidence suggests there could be similar effects in humans.
Male embryos dominated their female twin counterparts when competing for valuable nutrients, the study showed. The females had a birth weight that was 10% lighter than their male twin siblings. The females were also less likely to make it through their first winter and had fewer offspring during their life than their twin brothers.
“Male and female embryos have different needs at early stages of development, and this means that the female embryos may lose out to their brothers,” said Dr Peter Korsten, of Edinburgh University.
Dr Korsten also added, “Our findings show the conflict between male and female siblings can arise very early in life, potentially with long-term consequences.”
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