Is having boys and girls related to temperature and climate change?

The ancient Greeks believed that the sex of children was directly related to the climate. It is easy to get pregnant with boys in hot weather and girls in cold weather, that is to say, the birth rate of boys and girls may change with the seasons.

Previous studies have long found that the sex and birth time of mice and bats are closely related to the environmental temperature. Although biologists have always been skeptical that the ratio of male to female is related to seasonal changes, in order to find out the relationship between fetal sex and environmental temperature, German researchers tracked the birth records from 1946 to 1995 and compared them with local temperature changes.

The results show that April to June is the month with the most boys born, and 10 is the month with the least boys born. Further analysis shows that the environmental temperature one month before fertilized eggs are combined, that is, the environmental temperature one month before sexual behavior, is an important factor affecting the sex of the fetus. High temperature environment is easy to make male fetus, low temperature environment is easy to make female fetus.

The researchers believe that the environmental temperature may affect the nature of sperm in testis, and the damage of continuous hot weather to X sperm may be greater than that of Y sperm, so the birth rate of boys is higher. The damage may be more than Y sperm, so the birth rate of boys is higher.

In addition, the increase of ambient temperature may have an indirect impact on the sex ratio. The higher the temperature, the stronger the desire to have sex, the more frequent sexual behaviors between men and women, and the more likely women are to get pregnant. Because Y sperm runs faster, it is easy to occupy an excellent pregnancy opportunity, so the birth rate of boys increases in high temperature environment.

Researchers believe that although the gender deviation is small, it will have serious consequences. Because there are already a few percent of boys, if the global climate is warming, it may further increase the gender ratio difference.