Microplastics identified as a possible factor in falling fertility rates worldwide

Tracey Woodruff, PhD, professor and director of Environmental Research and Translation for Health (EaRTH) at the University of California, who was not involved in the study, told MNT: “This study evaluates the types of plastics found in the testicles, and it is no surprise that PE is the most common – as PE is the most commonly produced plastic – it is used in plastic bags, bottles, food containers, films for carpets, etc. “, adding that “Ultimately, if this product is used, there is a good chance that some of it will end up in our homes and our pets. As for health effects, this adds further evidence to our work showing that MP (microplastics) are suspected of having adverse effects on the male reproductive system.

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Influence of microplastics on fertility

However, it is unclear what type of effect microplastics have on male fertility.

Researchers found that certain types of microplastics were associated with lower sperm counts and testicular weight. The study indicates that these results reached a level of “statistical significance”.

However, one type of microplastic was associated with increased sperm counts and two others were associated with increased testicular weight. However, the researchers determined that these results were not statistically significant.

James Kashanian, MD, who was also not part of the study, told MNT that the current study highlights the impact of human-made environmental factors on men's reproductive health.

“Higher levels of these microplastics can potentially have deleterious effects on testicular function, i.e. testosterone production and sperm production. Unfortunately, many environmental factors, like those studied in this paper, accumulate over decades and are not easily reversed,” Kashanian said.

Although alarming, the results are far from conclusive as the study has a number of limitations.

First, it looked at a small number of samples, samples collected in one region of the United States, and second, the samples were from 2016, a factor that could have impacted the results.

“Researchers also recognize that the humans from whom the samples came generally did not die naturally, so experts cannot expand the results to an entire population,” MNT noted.

The researchers also concluded that the results cannot establish causality.

They noted that their research “highlights the need to determine the dose-response effects of these microplastics and to conduct mechanistic studies on the reproductive system.”

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Fertility rates falling around the world

Governments around the world must prepare for massive changes in the coming decades as global demographic trends shift, according to a study published in The Lancet on March 20.

The study concludes that by 2050, people living in 155 of the 204 countries and territories surveyed will have fewer babies than would be needed to maintain a stable population.

“These future trends in fertility rates and live births will completely reconfigure the global economy and international balance of power and require a reorganization of societies,” Natalia Bhattacharjee, demographic statistician at the Institute for Health Metrics and Evaluation (IHME) in the USA. told Science Alert.

The study noted that in the 1950s, every woman on the planet had just under five children, a number that has dropped to just over two children per woman in 2021.

The study also notes that the results are not entirely bad.

“In many ways, the fall in fertility rates is a success story, reflecting not only better and readily available contraception, but also the choice of many women to delay or have fewer children, as well as greater opportunities education and employment,” said association member Stein Emil Vollset. ” from the Future Health Scenarios Forecasting Team told Science Alert.

Researchers estimate that if these trends continue, the number of people on the planet will peak at around 9.7 billion in 2064, before falling to 8.8 billion by the end of this century.

In the United States, declining fertility rates are not blamed on health or environmental factors, but rather on social and economic problems.

Scott Galloway, a professor at New York University's Stern School of Business, said in an interview with Fortune: “For the first time in the history of our country, a 30-year-old man or woman is not does not carry as well as his or his wife. his parents were 30 years old. It is the social pact that is collapsing. Millennials and Generation Z are facing sky-high mortgage rates, soaring housing prices and inflation, all of which are slowing down some traditional, even historic milestones, like having a child.