Do microplastics cause infertility? This question has gained increasing attention as studies report microscopic plastics in human tissues, including reproductive organs. While these findings have raised understandable concerns about infertility and reproductive risks, interpreting the science is complex and current evidence cannot conclude microplastics are impacting human fertility.

Importantly, fertility trends are influenced by many well-established factors, such as age and other health factors, and since the science of microplastics is still relatively new, the uncertainty about microplastics is compounded by the fact that measuring them in the human body remains technically challenging.

Challenges to measuring microplastics in the body 

Scientists have reported finding micro- and nanoplastic particles in human tissues and fluids. However, experts emphasize that the methods used to detect and measure these particles are still evolving and face significant challenges before the results of such measurements can be reliable (Lamoree et al., 2025; Xu et al., 2025).

One widely discussed study reported microplastics were found in all samples of human testicular tissue from 23 men (Hu et al., 2024). Subsequent scientific reviews have identified several important limitations related to how the measurements were conducted (Lamoree et al., 2025), including:

• Use of an analytical method with known limitations in biological tissues. The study relied on pyrolysis gas chromatography–mass spectrometry (Py-GC/MS), which identifies materials based on chemical fragments rather than directly observing particles. In biological samples, naturally occurring compounds such as lipids (i.e., fats) can produce chemical signals similar to those from common plastics, particularly polyethylene and PVC, and can’t easily be distinguished from one another using only this method. Notably, the Hu et al. study reported the highest concentrations for polyethylene and PVC, the polymers that are particularly susceptible to misidentification when using the Py-GC/MS method in biological tissues. This suggests the findings may reflect methodological limitations rather than true concentrations in the tissue. (Lamoree et al., 2025; Xu et al., 2025).
• Limited documentation and validation. Scientific reviewers noted that the Hu et al. study included insufficient detail about sample processing, storage, and quality controls, as well as a lack of validation to demonstrate that measurements were accurate and reproducible (Lamoree et al., 2025).

Because of these limitations, scientists caution that uncertainty remains about much of the research in circulation today. Detecting particles, particularly when using methods with known limitations, does not demonstrate health effects or reproductive harm. 

Animal studies raise questions but have limitations and may not reflect real-world exposure 

Some laboratory studies in animals have reported reproductive effects after exposure to microplastics, contributing to concern about possible human health implications (Chartres et al., 2024).

First and most importantly, exposure levels are often far higher than what humans would experience in everyday life and don’t represent realistic conditions. In the area of toxicology, dose matters: at sufficiently high exposure levels, every substance can produce biological effects, even water. Results from extreme laboratory conditions do not necessarily reflect risks under typical human exposures. 

Other factors should be considered when interpreting reproductive outcomes in animal models, including natural variability in sperm counts and the influence of small sample sizes (Coffin et al., 2022; Fitch et al., 2025). Importantly, sperm count alone does not directly predict fertility, and substantial changes may be required before meaningful biological effects occur. 

However, most animal experiments have important limitations that only come to light when a thorough review of the science is conducted (Fitch et al., 2025). Reproductive toxicity tests have clear, internationally accepted guidelines (e.g., OECD Test Guidelines) that must be followed to ensure the data is reliable. The authors in the Fitch et al. study critically assessed 24 studies that measured exposure to microplastics and their potential effects on reproduction and fertility against a set of established criteria. It is important to note that these criteria apply to all reproductive and fertility studies, regardless of what material or chemical is being tested. Meeting these criteria are the baseline expectations for reliable studies, and failing to meet these criteria means that it is difficult to interpret the results as reported.

All 24 of the studies assessed had significant flaws including the lack of appropriate controls, inconsistent reporting of body weight and estrous cycle data, inappropriate sperm collection methods, insufficient sample sizes, and incorrect statistical methods are only some of the flaws noted. The limitations in these studies mean they can be used to explore possible biological mechanisms, but they are not of sufficient quality to demonstrate an adverse effect to the animals or a risk to humans.

Human fertility trends are influenced by many factors  

Reproductive health is shaped by numerous factors, including age, lifestyle, underlying medical conditions, environmental exposures, and access to healthcare. 

One of the most important and well-established influences on fertility is age. In the U.S., the mean age of mothers at the time of their first birth has increased by nearly two years since 2010 (Westrick-Payne, Manning, 2025), a trend also observed in men, especially in developed economies (Almeida et al., 2017). Changes in hormones, decrease in cell quality, and other age-related factors all result in a gradual decrease in fertility with age. This demographic shift is widely considered a major contributor to observed changes in birth rates. 

To further illustrate how difficult it is to assess the topic of fertility, trends in male reproductive health do not necessarily show a consistent decline. A recent study analyzing more than 18,000 semen samples from more than 15,000 men found sperm concentrations have increased over the past 15 years, the exact opposite finding of other studies (Nolan et al., 2026). The authors emphasise the importance of regional differences and local factors, like healthcare access and lifestyle factors, are critical to understanding of overall male fertility trends.

In one small study, the researchers measured microplastics in human follicular fluid samples collected from women undergoing assisted reproductive treatment at IVF (In Vitro Fertilization) (Montano et al., 2025). These women were admitted with a variety of different diagnosis, which may have different biological causes. The researchers reported a mild association between increased microplastic concentrations and increased Follicle-Stimulating Hormone (FSH); however, all measurements of FSH were within normal parameters (i.e., 1.4 to 9.9 mIU/mL (follicular phase)) and so it is unclear if this is a biologically relevant finding (Lanciotti et al. 2018). No correlation between microplastics, fertilization outcomes, miscarriages, or live births were observed.

Simply put, this study is too small to make any conclusions regarding female fertility and microplastic exposure and the one correlation was still within normal biological parameters. More research is needed in this area before a conclusion of determination can be made.

Taken together, these findings suggest that changes in fertility patterns could be explained by demographic and lifestyle factors, particularly delayed parenthood, rather than a single environmental exposure. The complexities associated with measuring fertility highlights that trends cannot be attributed to one factor such as microplastics.

The bottom line 

Microplastics research is advancing rapidly, but current evidence does not demonstrate that microplastics are causing infertility in humans.

What scientists do agree on is the need for better measurement methods, scientifically robust studies, and transparent, reproducible data to inform decisions about potential risks and appropriate responses. Supporting rigorous research, rather than drawing conclusions too early is the most effective way to protect public health and guide sound policy.

REFERENCES 

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