Could CLIMATE CHANGE determine the sex of your child? Warmer temperatures are linked to a rise in girls being born
- Study in Japan suggests temperature affects the sex of babies
- More girls were born than boys during a period of rising temperatures
- Experts found unborn boys are more vulnerable to external stress factors
- Previous studies also found that temperature affects the sex ratio
From the position of a woman’s ‘bump’ to the movement of a suspended ring, there are many old wives’ tales that claim to be able to predict the sex of an unborn child.
But now mothers-to-be may want to keep an eye on the world’s weather, as experts have suggested that changing temperatures affect the sex of babies.
A Japanese study has found that more baby girls are born, compared to boys, when temperatures rise in the country.
A Japanese study has found that more baby girls are born, compared to boys, when temperatures rise in the country. It reinforces previous research that suggests temperature plays a role in the sex ratio - but some of the results contradict each other
‘The recent temperature fluctuations in Japan seem to be linked to a lower male:female sex ratio of newborn infants, partly via increased male foetal deaths,’ according to scientists from M&K Health Institute and Shimizu Women's Clinic, both in Hyogo, as well as the University of Copenhagen.
‘Male concepti seem to be especially vulnerable to external stress factors, including climate changes,’ they wrote in a study published in the journal, Fertility and Sterility.
Previous studies have also shown that the sex ratio is sensitive to factors such as temperature.
Researchers recently found that more girls are born in tropical countries than boys, but warmer periods in Northern Finland led to more baby boys being born, Smithsonian reported.
This reveals that some studies seem to contradict one another.
Earlier this year, pollution in central Scotland was linked to a skew in the sex ratio in favour of girls.
Previous studies have shown that the sex ratio is sensitive to factors such as temperature. Researchers have found that more girls are born in tropical countries than boys, but warmer periods in Northern Finland led to more baby boys being born. A stock image of a pregnant woman is pictured
To come up with the latest results, experts in Japan studied birth records and miscarriages in Japan between 1968 and 2012.
Overall, more girls were born compared to boys and temperature fluctuations – particularly from a hot summer to a cold winter – saw the sex ratio become temporarily more pronounced.
The study claims that temperature fluctuations have influenced the ratio, but makes it clear that climate change may not be responsible for skewing the number of girls and boys that are born.
...AND CLIMATE CHANGE AFFECTS POOR URBAN AREAS THE MOST
Climate change affects people living in poor parts of cities more than more affluent residents, a study claims.
Joyce Klein Rosenthal, a researcher at Harvard University said that people living in poor neighbourhoods are at the most risk of suffering from heat-related illnesses.
This is because poor areas tend to be more cramped and are hotter overall than more desirable places, which may have wider boulevards or parks, she told Time magazine.
In poorer neighbouroods, buildings may be built from cheaper materials that retain heat and few people may own air conditioners.
In a study of New York City, Dr Rosenthal found a link between the affluence of neighbourhoods and the number of people who died from heat-related ailment, which are known to affect senior citizens.
Olga Wilhelmi, a researcher at the University Corporation for Atmospheric Research, said that climate change effects poorer neighbourhoods more because many people do manual labour. They may spend long periods of time outside in high temperatures and come home to a hot building where they are more likely to suffer from heat stroke, she said.
It does however seem to reinforce previous studies that have found that male foetuses are more susceptible to events that can stress pregnant women, such as extreme heat waves.
‘Two climate extremes, a very hot summer in 2010 and a very cold winter in January 2011, showed not only statistically significant declines in sex ratios of newborn infants 9 months later in June 2011 and October 2011 but also statistically significant increases of foetal death rates immediately, in September 2010 and January 2011,’ the researchers wrote.
Animal studies have shown that rainy periods lead to more male chimpanzees, while loggerhead turtles produce more female offspring in warmer waters. Temperature is also known to determine the sex of reptiles.
If the world is getting hotter and rising temporaries do favour the birth of girls, a change to the global sex ratio may happen one day. A study in 2002 found that 101 boys are born compared to 100 girls.
Another study has found that climate change affects people living in the poor parts of cities (such as new York, pictured) than more affluent residents. This is because poor areas tend to be more cramped and are hotter than more desirable places, which may have wider boulevards or parks