Testicular dysgenesis syndrome (TDS) – deteriorating male reproductive health
Testicular dysgenesis syndrome (TDS) is used to describe a spectrum of male sexual disorders that may be apparent at birth or show up in adulthood. They are thought to be linked to abnormal events that occur when baby boys are developing in-utero. These disorders affect a surprisingly large number of men. CHEM Trust has produced several publications summarising the state of the science, in particular a report by Professor Richard Sharpe.
The disorders evident at birth include cryptorchidism where one or both testicles do not descend into the scrotum and hypospadia where the urethral opening is wrongly located on the penis. In many cases both of these disorders require surgical correction. In adulthood, low sperm counts/infertility and testicular cancer are also becoming increasingly common in young men. These 4 disorders make up TDS and are considered to be interconnected in many cases, with baby boys with undescended testes being at greater risk of having low sperm counts and developing testicular cancer.
It is generally thought that abnormal development of the cells in the testicles, plus interference with sex hormones, eg testosterone (the male hormone), are probably the cause. Genetic, lifestyle and environmental factors may play a part, but for testicular cancer, the increase over the last 40 years is such that it must be something in the environment or lifestyle factors that are largely to blame, because genes in a population do not change that quickly. It’s a hypothesis that is the cause of much concern within the medical community which has been written about extensively in many respected journals, including The British Medical Journal and The Lancet.
Several man-made chemicals have the ability to block the male hormone. In animals these chemicals can give rise to undescended testicles, malformation of the penis and low sperm counts. Therefore, there is concern that these chemicals may have similar effects in humans. Concerns are increased because it is known that many of these chemicals can act together to cause effects even when each is below a concentration to cause an effect on its own. However, it is very difficult to prove or disprove whether these chemicals are actually causing the demasculinising effects that are now being seen in men. Nevertheless, many scientists are now raising their concerns about the action of these endocrine or hormone disrupting chemicals, which can block the male hormone testosterone.
The link to effects on wildlife
The concern for human health is underlined by findings in wildlife. Male fish, amphibians, reptiles, birds and mammals have all been harmed by chemicals in the environment, and feminisation is widespread. See CHEM Trust’s December 2008 report entitled “Effects of Pollutants on the Reproductive Health of Male Vertebrate Wildlife – Males Under Threat”.
Trends in many reproductive disorders, including testicular cancer, are showing a worrying increase. The seriousness of the male reproductive health problem is highlighted by recent health statistics.
- In many industrial countries, testicular cancer is now around twice as common as it was thirty to forty years ago.
- 2007 data indicate that 6 baby boys in every 100 born in the UK have undescended testes.
- 1 in 6 young men in several EU countries (including data from Scotland) have sperm counts so low that they are sub-fertile and may have difficulty in getting their partners pregnant.
Several recent studies have shown associations between prenatal or postnatal exposure to certain pesticides or phthalates and effects on reproductive disorders or male hormones.