In heavily polluted areas, the number of baby boys born is lower than that of baby girls, along with a higher rate of miscarriages. The cause may be due to pollution leading to genetic defects.
A research team from the University of São Paulo, Brazil, investigated the gender imbalance in various living environments. They summarized birth registration data and the number of children born from January 2001 to December 2003. The statistics revealed that in clean air areas, 51.7% of newborns were male. This percentage dropped to 50.7% in heavily polluted regions.
Next, the research team compared the male-to-female ratios in the offspring of several male mice exposed to clean or polluted air during the first four months. These male mice were paired with females not exposed to polluted air. The results showed that males living in a clean environment produced offspring at a ratio of 134 males to 100 females, while in the group exposed to polluted air, the ratio was 86 males to 100 females. The study also indicated that those inhaling toxic air exhibited abnormal sperm production activity.
According to the lead researcher, Jorge Hallack, one potential cause could be that air pollution stimulates the formation of genetic defects, preventing the fetus from surviving. Another hypothesis is that “pollution affects placental function,” leading to fetal starvation and death.
Mỹ Linh (according to BBC)
