Researchers found yesterday that levels of pesticides which were thought to be harmless could cause cancer in babies and young children. The study, conducted at the Liverpool University, shows that low levels of chemicals found in pesticides and plastics could affect the development of babies while still in the mother's womb and could increase their risk to get cancer later in life. These chemicals pass to humans from eating meat and dairy products and can also be transferred from a mother to her baby through breast milk. The organochlorines accumulate in the breast milk, increasing the baby's vulnerability while being breastfed. In the idea that the link between pesticides and cancer has been disputed for a long time, scientists who have conducted the present study said the evidence is enough for parents to consider switching to organic diets to avoid contamination, also saying authorities should revise the levels of chemicals permitted. There is proof that some people might have a vulnerability caused by genetic factors to these chemicals. "It seems to be the most vulnerable members of society: the developing fetus, the developing child and adolescent and the genetically predisposed, who are at risk of developing cancer following involuntary exposure to environmental contaminants. This may be an appropriate time for governments to adopt the precautionary principle until substances to which members of society are involuntarily exposed are proved safe from long-term, low-level effects on human health," said the study.