Evaluation of the impact of environmental pollutants on the sex ratio: a systematic review.

In several industrialized countries, there has been a report of a decrease in the proportion of male births. The current study is designed to perform a systematic review and present a comprehensive summary of current epidemiological evidence of an association between exposure to the mentioned pollutants and sex ratio. The present systematic review was executed according to the PRISMA protocol. A comprehensive online search was performed in PubMed Medline, Scopus, Web of Science, Embase databases, Google Scholar, and the World Health Organization databases from 2000 to September 2023. After searching all databases, 20 articles were included in this systematic review. Regarding the studied pollutants found that exposure to increased PM10, PM2.5, and Nitrogen dioxide (NO2) levels was significantly associated with the sex ratio. Both maternal Benzophenone (BP)-2 and paternal BP-2 were significantly associated with an excess of female births. Finally, it must be said that the effect of some environmental pollutants on the sex ratio is undeniable. However, the sex ratio is the result of multiple factors that interact simultaneously during pregnancy. Additional research is required to examine the mechanisms responsible for the change in sex ratio.