Women's Exposure to Higher Lead Levels Increases the Chance of Having Male Offspring

A woman's exposure to higher lead levels increases the chance of having male offspring, as per a new study.

Researchers in Japan conducted research to explore the effects of lead exposure on women's fertility and the secondary sex ratio between males and females in Japan.

The new study came at a time when Japan is continuing to experience a gradual population decline over recent years.

Although the lead-based approach in the study is relevant in the East Asian country, it can also be used as a basis to predict population growth in other countries in the future.

Childbirth and Lead Exposure

(Photo : Philip Fong/AFP via Getty Images)

The new study was published in the journal Science of the Total Environment, which examined the correlation between blood lead levels during the second or third trimester of pregnancy, as well as the secondary sex ratio.

The study indicated that the higher the blood level, the greater the secondary sex ratio.

The study also found that maternal exposure to lead also increased the rate of male birth.

Researchers discovered the blood lead level of a mother declines if there is also a decrease in air lead level. This variation may also affect the secondary sex ratio may also be connected.

Scientists from the Graduate School of Medicine of Tohoku University in Sendai, Japan, determined lead exposure and sex ratio are parallel with one another.

This means that higher lead levels in a mother's blood can increase the percentage chance that a woman will bear a male baby.

Meanwhile, their parallel relation indicates there will be a lower chance to give birth to a male offspring if the mother's blood has a lower blood lead level.

Although the discovery is not absolute, the connection of the lead to gender is important in terms of predicting the sex of an offspring.

The study acquired its data by including pregnant female participants.

Based on the aforementioned result, the study found why there is a declining male population in Japan, as cited by Science Daily.

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Japan Population

According to the World Population Review of the US Census Bureau, the population of Japan has been declining since 2009.

The US Census Bureau indicated that Japan's population is approximately 125 million as of March 2022. However, it is reportedly expected to decline below 100 million by 2058.

The US Census Bureau also showed there is a significant negative population growth rate in Japan over recent years, starting from 2015 to early 2022.

Unlike between 1955 and 2010, there is a positive growth rate in Japan prior to 2015.

Furthermore, the US Census Bureau stated Japan is still the oldest country in the world.

This entails that a large portion of Japan's population is old individuals aged 65 and above.

The US population agency also highlighted that there is only a small gap between the ratio of males and females.

The new research from Japan is not only vital to the country but it can also be used in other countries with different demographic profiles and population data.

Although lead is a dangerous chemical element, the new approach may help forecast population increase more accurately in the future.

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