A call has gone out for the government to ban 'gender-bending' chemicals after they were found in six out of 10 plastic toys tested by a green group. The chemicals, phthalates, are banned from children's products in Europe and the United States after being linked to abnormalities in the reproductive system during fetal development and hormonal malfunctions in children. But a biochemistry professor said Hong Kong parents should not be too worried as large-scale exposure to the substances over a long time was needed before any damage was done. An independent laboratory appointed by Greenpeace tested 20 children's products bought in Beijing, Shanghai and Guangzhou and 10 bought in Hong Kong. Out of the 30 samples, 21 contained phthalates. Nineteen of the 21 positive samples contained more than 10 per cent phthalates by total weight. In Hong Kong, one of the six products with phthalates contained nearly 30 per cent of the chemicals. 'Governments in the EU and North America have all recognised the serious health concerns of phthalates for children, yet in China and Hong Kong, kids are unprotected from these harmful toxins,' saidGreenpeace campaigner Vivian Yau. 'We urge the Hong Kong government to follow suit and immediately ban the use of phthalates in children's products.' Phthalates are plastic softeners commonly added to PVC materials. Greenpeace said exposure had been associated with genital abnormalities in newborn babies, especially boys. Animal studies have also suggested that the chemical may damage reproductive development by disrupting hormone levels. John Ho Wing-shing, associate professor of biochemistry at Chinese University, played down the dangers. 'Yes, phthalates are banned in the EU and the US due to safety concerns but they are not lethal. Any health effect that the chemicals may cause will only emerge after chronic exposure and in large amounts,' he said. While the chemicals could be absorbed through breathing and skin contact, once added to plastics they became part of the compound and would not readily come out, he said. Since 1999, the EU has banned the use of six types of phthalates in children's products and three were selected in February to be completely phased out of the EU market. The US and Australia also have bans and restrictions on phthalates in children's products.