Boys born to women exposed to hairspray in the workplace may have a higher risk of being born with a genital defect.

Imperial College London scientists talked to women who had babies with hypospadias, where the urinary tract is found away from the penis.

They reported that hairspray exposure more than doubled the risk.

The study in the journal Environmental Health Perspectives, said it was too early to say for certain that hairspray was the cause.

The incidence of hypospadias has risen sharply in recent decades, and some experts have pointed the finger of suspicion at chemicals called phthalates, found in some plastics, including those found in hairspray.

Phthalates have the ability to disrupt hormones, and have been banned in toys in the EU for some years.

The latest study looks not at personal use of hairsprays, but at their use, potentially in higher doses, by workers such as hairdressers and beauty therapists.

A total of 471 women whose babies had been born with hypospadias were interviewed, as were a similar number of women with unaffected children.

Roughly double the number of women in the "hypospadias" group revealed that they had been exposed to hairspray through their job compared with those with unaffected babies.

"Pregnant women will need to make their own choices about whether or not to avoid these kind of exposures" said Professor Paul Elliott, who led the study.

Vivienne Parry, author of The Truth about Hormones, expressed concerns about the methods used in the study.

She said: "If this were a study only of hairdressers, whose occupation exposes them to hairspray on a regular basis, then I would be a lot more convinced than I am by a study that has asked people of different occupations and lifestyles to recall their exposure levels."

Another finding of the study provides further backing of the government's recommendation that pregnant women should take extra folate to prevent similar defects to hypospadias, which arise early in pregnancy.

Women who took folic acid in the first three months of pregnancy were a third less likely to have a baby with hypospadias, according to the study.