Fertility is the subject of a new documentary, Infertile, featuring University of Nottingham expert Professor Richard Lea, as the film examines how exposure to man-made environmental chemicals has been linked to declining reproductive function in humans and animals.
Released on 8 July and produced by Escapade Productions, the documentary steps into uncomfortable territory: the daily chemical soup of modern life and its possible role in one of the most quietly consequential health issues of our time. Not exactly light viewing with a biscuit and a cup of tea, then, but important all the same.
Why Infertile Is Looking At Environmental Chemicals
Professor Lea, from the University’s School of Veterinary Medicine & Science, appears in the film to discuss the scientific evidence behind reproductive changes being seen across species.
Professor Lea says: “We are exposed to mixtures of chemicals day in and out, and many of these chemicals block or mimic hormone action. The implications of this, is that the developing unborn baby and newborn, that relies heavily on hormonal cues in order to develop properly, may be affected by exposure with consequences for reproductive health in adult life.”
That is the nub of the issue. Hormones are not optional decorative extras in early development; they are part of the body’s instruction manual. If chemicals interfere with those signals at vulnerable stages, researchers are asking whether the effects may echo later in life.
The Human Health Picture
The documentary places Professor Lea’s work within a wider discussion about fertility and reproductive health.
In humans, sperm counts have declined for more than 50 years. There has also been an increase in baby boys born with undescended testicles, known as cryptorchidism. In women, reproductive health has also declined, with increased incidences of premature ovarian failure, early puberty and an increased incidence of breast and other reproductive cancers.
None of this is simple. Biology rarely is. It tends to arrive with caveats, confounders and enough moving parts to make a golf swing look like Lego.
“Although these changes over time are associated with exposure to chemical pollutants, it’s difficult to demonstrate cause and effect,” says Professor Lea.
That distinction matters. The documentary is not presenting a neat villain with a moustache and a laboratory coat. It is examining evidence, association and mechanisms — the less theatrical, more useful machinery of science.
Why Stud Dogs Became Part Of The Story
To explore the question further, Professor Lea and colleagues studied sperm quality in healthy stud dogs from an assistance dog breeding programme.
Professor Gary England, also from the University’s School of Veterinary Medicine & Science, working with Professor Lea said: “Since the dogs live in normal homes and are regularly checked for reproductive and general health, we could investigate changes in sperm quality over time.”
That made the dogs a particularly valuable population to study. They were not laboratory abstractions. They lived in ordinary homes, shared human environments and received regular health monitoring. In other words, they offered researchers a way to examine real-world exposure and reproductive change over time.
In a pivotal paper published in 2016, and in subsequent studies, Lea and colleagues found that sperm quality had declined in these stud dogs at a rate that parallels that seen in humans. Within the same population of dogs, more pups were also being born with undescended testes, reflecting a pattern also seen in humans.
The Testicular Tissue Evidence
The research then moved closer to the site of sperm production itself.
Professor Lea said “Since numerous dogs are castrated for veterinary reasons, this provided us with surplus tissue that would otherwise be discarded. Using these samples, we have shown that chemicals are present in testes where sperm is produced and worryingly, they are able to reduce the motility of sperm in short-term incubation, even at the concentrations detected.”
That is a stark finding. Sperm motility is not a niche technicality. It is central to reproductive function. If chemicals found in testicular tissue can reduce motility under experimental conditions, it gives scientists another reason to take environmental exposure seriously.
Again, the story is not a cartoonish panic about modern life. It is a scientific argument for scrutiny, caution and better public understanding.
Sheep, Sewage-Based Fertiliser And Shared Exposure
The documentary also explores studies involving sheep exposed to chemicals in processed human sewage-based fertiliser. Professor Lea and colleagues from the Universities of Glasgow and Michigan describe work involving fertiliser commonly used by farmers, which contains mixtures of chemicals primarily originating from humans.
As pregnant ewes graze those pastures, both they and their unborn lambs may be exposed to chemical mixtures that approximate human exposure.
It is a grimly efficient circle: the substances used, consumed and discarded by people can return through the environment, not as dramatic monsters from the deep, but as low-level mixtures in the places animals feed and develop.
Why The Documentary Matters Now
Infertile brings this work together with other studies in humans and animals around the world. Its purpose is not merely to frighten viewers, although a little discomfort may be unavoidable. Its more useful role is public awareness: taking a complex scientific issue and putting it in front of people who may never read a reproductive toxicology paper over breakfast.
Professor Lea said: “The release of this documentary at a time when global fertility is declining, is crucially important. We must take action now to mitigate against the effects of environmental contaminants – ultimately this will protect reproductive health in future generations!”
Professor Lea also attended the launch of the Plastic Babies campaign in the House of Lords on 9 June, emphasising the need to limit exposure of babies to plastics during the first 1000 days of life.
For a subject so often discussed in private, fertility is becoming a public health conversation with environmental, medical and generational consequences. Infertile appears determined to pull that conversation out of the shadows, put the evidence on the table and ask whether modern life is leaving a biological signature we can no longer afford to ignore.
