A link between hairspray and a genital defect in boys has been uncovered.

A link between hairspray and a genital defect in boys has been uncovered.

Researchers found that women exposed to hairspray in the workplace during early pregnancy more than double their chances of giving birth to a son with hypospadias.

The defect normally affects around one in 250 boys in the UK, causing the urinary opening to be shifted beneath the penis.

Although it can be corrected by surgery before a boy's first birthday, more severe cases can lead to urinary, sexual and fertility problems.

Hormone disrupting hairspray chemicals called phthalates, which can affect reproductive development, are believed to be behind the connection.

But the study showed that taking folic acid reduces the risk of giving birth to a child with the condition by 36%. An increased risk was only seen in women whose jobs led to high exposure to hairspray chemicals, such as hairdressers, beauty therapists, research chemists and factory workers.

The link was made after researchers conducted detailed interviews with 471 women whose sons had been referred to surgeons for hypospadias, and 490 "control" mothers of boys not born with the defect.

Exposure to hairspray in the first three months of pregnancy was found to increase the chances of having a son with hypospadias two-to-three-fold. The risk was reduced by taking folate supplements over the same period.