A boy or a girl? Nature does not meet the wishes of the parents. Those who believe that the chances of giving birth to a girl or a boy are equal are fundamentally wrong. Never the ratio between newborn boys and girls was 1: 1. Always someone is born more, someone is less. Several factors influence these fluctuations.
The weight of the mother prior to conception has a decisive influence on the sex of the child. Italian researchers observed 10,000 pregnant women. The results showed that women weighing less than 54 kg, more often give birth to boys than others.
The sex of the child can be affected by various natural anomalies and natural disasters. So in the countries subjected to drought and, as a consequence, hunger, girls were born twice as often. American researchers found that after a period of extreme hunger, drought and other natural disasters in general, very few male children are born.
The quality of sperm and sex of embryos is influenced not only by malnutrition, but also by a number of other various factors. Specialists also noted a marked change in the ratio of boys and girls in East Germany after the fall of the Berlin Wall. In 1991, they were born to several hundred thousand boys less, and scientists explain this by saying that this year people were more agitated under the influence of certain factors - some political events. After earthquakes and natural disasters, the number of boys is also decreasing. Stress is again shown as the main reason.
The ratio of sex affects the season. At conception in the autumn period more boys are born, and the chances to give birth to a girl are greater if the conception occurred from March to May.
Male embryos have an advantage at the stage of getting into the uterus. The cells of the male embryo are divided faster, and all the processes associated with metabolism work faster. But with the rapid division of cells, the probability of anomalies in development increases. The effect of toxins and other harmful substances is increasing. Thus, during pregnancy and immediately after birth, the likelihood of abnormal development of boys is greater.
Scientists are still arguing whether the sex of the child depends on the chemical pollution of the environment, whether it affects the ratio between the born girls and boys. American researchers are convinced that these factors affect the ratio between newborns. For example, seven years after the accident involving the release of toxic dioxin in the region, there were twice as many girls as boys.
Dependence on the factors associated with certain substances has already been proven by scientists. They also affect sperm and prevent the development of the embryo in the uterus. Nicotine is one of these harmful substances. Japanese and Danish researchers found that smoking before conception and during pregnancy significantly reduces the likelihood of the birth of boys. And if both parents smoke, the probability of a girl's birth rises by one third compared to non-smokers.