However, no previous study has examined the influence of prenatal exposure.

Prenatal exposure has been linked to impaired fetal growth and development.

Studies have shown an association between prenatal exposure to environmental tobacco smoke and conduct disorder in children.

Recent studies have emphasized the importance of prenatal exposure to hormones in shaping sexual identity.

A 1995 survey in the US found that between 30,000 and 160,000 cases of prenatal exposure to cocaine occur each year.

There is also growing evidence that prenatal exposure to air pollutants can hurt fetal growth and cognitive development.

The consequences of prenatal exposure on neurobehavioral development during childhood have not previously been reported.

There is no direct proof that prenatal exposure to the tobacco chemicals actually puts children at higher risk of cancer.

They also showed that prenatal exposure to aspirin and antibiotics is correlated with lower performance on intelligence tests as well.

A final area of concern to those wishing to avoid prenatal exposure to toxicants would be pesticides.