What if plastic pollution was already affecting the health of unborn children? A team from the University of California at Riverside has just shown, in mice, that a simple
paternal exposure to microplastics can be enough to disrupt the way offspring manage fat and sugar, well before any bad lifestyle habits.
Published in December 2025 in the journal Journal of the Endocrine Societythis work focuses on plastic particles less than 5 millimeters in size, omnipresent in air, water and food. These microplastics have already been spotted in human reproductive tissues, while metabolic disorders in children are progressing everywhere. And above all, girls seem particularly vulnerable.
Father’s microplastics: obesity especially among mouse daughters
In this study, male mice were exposed to microplastics while fed a standard diet and then mated with unexposed females. Their offspring, called the F1 generation, were then fed a diet very rich in fat, close to a Western diet, in order to more clearly reveal possible disturbances in the
metabolic health.
The researchers found that females born to exposed fathers gained more weight and developed signs of
diabetes compared to litters of males, although all follow the same fatty diet. The researchers observed that although the male offspring did not develop diabetes, they showed a notable, albeit modest, reduction in body fat. In contrast, female offspring showed a reduction in muscle mass, accompanied by an increased risk of diabetes.
“The exact reasons for this sex-specific effect are not yet clear“said Changcheng Zhou, professor of biomedical sciences at the UCR School of Medicine and lead author of the study. “In our study, female offspring developed diabetic phenotypes. We observed overexpression of pro-inflammatory and pro-diabetic genes in their livers – genes already associated with diabetes. These changes were not observed in male offspring“.
In spermatozoa, small RNAs marked by microplastics
To understand how these effects are transmitted, the team used specialized sequencing technology of
sperm called PANDORA-seq. They discovered that exposure to microplastics changes the contents of sperm cells, affecting small molecules that regulate the activation and deactivation of genes (non-coding RNAs).. These small non-coding RNAs in sperm could contribute to the intergenerational transmission of paternally acquired cardiometabolic disorders.
Schematically, these molecules do not modify the DNA, but act as real variators which regulate the expression of certain genes upwards or downwards from the early stages of embryonic development. “To our knowledge, our study is the first to show that paternal exposure to microplastics can affect sperm small non-coding RNA profiles and induce metabolic disorders in offspring“, said Prof. Zhou.
What lessons for future human fathers?
The study thus reveals that the effects of plastic pollution are not limited to the person directly affected; it can create a biological imprint that makes children more likely to develop chronic diseases.
“Our discovery opens new perspectives in the field of environmental health, highlighting the importance of both parents’ environments on the health of their offspring.” says Professor Zhou. “Although these results were obtained in mice, they could have implications for humans. Men who plan to become fathers should consider reducing their exposure to harmful substances such as microplastics to preserve their health and that of their future children.”.
The University of California team will continue their work to learn whether maternal exposure produces similar risks and identify ways to mitigate these metabolic changes.