A condition which causes baby boys to be born with deformed penises is becoming more common in Sweden, for reasons unknown to scientists.
Researchers in Sweden assessed data collected on Hypospadias between 1973 and 2009. They found that before 1990, only 4.5 boys out of every thousand had the condition known as hypospadias. But after 1990, the figure had risen to 8 per 1000 boys.
In an attempt to explain the rise, the experts from Stockholm's Karolinksa Institute considered factors known to cause the defect, including low-birth weight, being born a twin, and parents who used IVF treatment to conceive.
However, scientists could not link the rise to any previously known causes, and instead concluded that an unknown factor was behind the trend, The Local reported.
Hypospadias can cause a combination of three separate problems: the meatus, the hole through which urine passes, is not being at the tip of the penis; the foreskin becoming gathered at the back of the penis with none at the front; and the penis being bent when stiff, according to the NHS.
While hypospadias is not life threatening, it can make it difficult to urinate standing up, and can make having sex difficult. The issues are usually fixed by an operation to move the meatus, and a circumcision to remove the foreskin.
Speaking with the Dagens Medicin newspaper, Anna Skarin Nordenvall from the institute did not reject the idea that chemicals that interfere with the hormones of mammals, known as endocrine disruptors, could be linked to the rise of hypospadias.
According to the WHO, endocrine disruptors are mostly man-made and are found in various materials such as pesticides, metals, additives or contaminants in food, and personal care products.
The chemicals have suspected associations with altered reproductive function in males and females, increased incidence of breast cancer, and abnormal growth patterns.