The Evil Twin
WASHINGTON (Reuters) - Women who have a male twin are less likely to marry and have children, perhaps because of being exposed to their brother's testosterone for nine months in the womb, researchers reported on Monday.Interesting health news. You have to wonder if there is any effect on the male twin due to his nine month exposure to female hormones and estrogen. Like an interest in going to mall or collecting large amounts of shoes.
A study of Finnish twins showed that women were 25 percent less likely to have children if their twin was a male. Those who did have children gave birth to an average of two fewer babies than women who had a twin sister.
Based on an analysis of 18th and 19th century data, researchers found women who had a male twin also were 15 percent less likely to get married, Virpi Lummaa of the University of Sheffield in Britain and Finland's University of Turku and colleagues reported.
"We show that daughters born with a male co-twin have reduced lifetime reproductive success compared to those born with a female co-twin," they wrote in their report, published in the Proceedings of the National Academy of Sciences. "This reduction arises because such daughters have decreased probabilities of marrying as well as reduced fecundity."
Researchers have long known that foetuses are influenced by hormones in the womb. Because male and female foetuses have similar levels of the "female" hormone oestrogen, girl twins are more likely to be affected by testosterone in the womb.
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Labels: Health and Medicine