Hypospadias, a condition which causes baby boys to be born with deformed penises, is becoming more common in Sweden, found a new study.
The researchers at Stockholm's Karolinksa Institute assessed data collected on Hypospadias between 1973 and 2009. They found, incidences of hypospadias in babies born after 1990 jumped significantly from 4.5 boys out of every 1,000 to eight per 1,000.
Scientists said that they had taken into account factors such as low-birth weight that could be linked to the condition. However, they could not link the rise to any previously known causes, and instead concluded that an unknown factor was behind the trend.
Hypospadias means the urethral opening is abnormally placed and can affect urination and sexual function later in life.
Lead researcher Dr Anna Skarin Nordenvall said that scientists could not rule out the theory that chemicals - specifically environmental agents known as endocrine disruptors - could be responsible for the trend.
Endocrine disruptors, which are mostly man-made, can be found in pesticides, plastics and various household products.