Dr Kristen Navara at the University of Georgia analyzed the world-wide data of sex ratios in 202 countries during a 10-year period. Scientist revealed that the sex of the baby was largely linked to the latitude. The results showed that chances of having a girl increase in countries closer to the equator. Other factors like socio-economic status and lifestyle differences were taken into account.
It is known that sex ratio is different around the world with global average slightly biased towards boys, which means that around 105 boys are born for every 100 girls.
Dr Navara discovered that 51.1 percent of boys were born in countries in tropical latitudes, if compared to 51.3 percent of boys born in countries in temperate and subarctic areas. Central African Republic was one of the countries that produced the most girls, while more boys than girls were born in China. This difference is statistically significant, Dr Navara says.
The difference in sex ratio is explained by a number of theories. Many evolutionary biologists believe that nature favors boys due to the fact that boys are at increased risk of premature death in comparison to girls. According to another version, during hard times women have more chances of conceiving boys because of their possibility to financially support their parents. Also some scientists say that during wars chances of having a boy are higher as nature tries to compensate for the loss of men.