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07-06-2011 | Article

More boys than girls born after nuclear radiation exposure


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MedWire News: Nuclear radiation can affect the gender odds of babies, a study of 40 countries suggests.

Information collected after atomic bomb tests and the Chernobyl power plant disaster, as well as from people living near nuclear facilities, suggests that more boys than girls are born after exposure to ionizing radiation.

Based on their study Hagen Scherb and Kristina Voigt, from the Helmholz Center Munich and the German Research Center for Environmental Research in Neuherberg in Germany, say that more research needs to be initiated to strengthen the evidence and "open minds to the danger of ionizing radiation."

Earlier research has led scientists to suggest that exposure to radiation causes men to sire an excess of sons, whereas the reverse may be true for women.

To investigate the issue further, Scherb and Voigt studied annual live births data from 39 European countries from 1975 to 2007 and also from the USA and a predominantly western and less Chernobyl-exposed part of Europe from 1950 to 1990.

The predominantly western European and US data showed a similar pattern consistent with a uniform reduction in gender odds between 1950 and 1964.

This was followed by an increase in the gender odds between 1964 and 1975, followed by a more or less constant decrease between 1975 and 1990.

The researchers say: "We conjecture that the increases in Europe and USA are a consequence of the globally emitted and dispersed atmospheric atomic bomb test fallout prior to the test ban in 1963 that affected large human populations overall after a certain delay."

The team further identified a "highly significant jump" in the European gender odds of 0.20% in 1987 following the Chernobyl accident, whereas no similar change was observed in the USA, which was less exposed to the effects of the disaster.

Gender odds were also significantly increased among German and Swiss people living within 35 km of active nuclear facilities.

The researchers say further information is needed to determine whether the change in gender odds is due to a reduction in the birth of girls or an increase in the number of boys being born.

They add: "Assuming that our approach is valid and realistic, it becomes clear that the deficit of births and the number of stillborn or impaired children after the global releases of ionizing radiation taken together may be in the range of several millions."

MedWire ( is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011

By Anita Wilkinson