Boys like it hot
Researchers investigating potential impact of temperature on gender, have shown that consecutive warm years can result in more men being born than women.
Researchers investigating potential impact of temperature on gender, have shown that consecutive warm years can result in more men being born than women.
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| The boys are back in town – well they could be if global temperatures rise |
Dr Helle, University of Turku, Finland said: “When the average temperature increased by 1oC for two years, there was an increase of 1% in the proportion of males.”
The team say it is likely that the explanations for these observations are varied. Sperm may be influenced by heat and cold stress. Additionally, the amount of steroids such as testosterone might be influenced by temperature, resulting in a larger proportion of males. In contrast, at the other end of the gestation period, temperature induced stress could favour female survival over males due to the enhanced vulnerability of male foetuses.
Dr Helle added: “Although the precise physiological and evolutionary mechanisms underpinning these observations remain unresolved, our results do show that environmental temperature may affect human birth sex ratio.”
