Pesticides used in our homes, gardens and lawns and sprayed on foods we eat are contributing to a dramatic decline in sperm count among men worldwide, according to a new analysis of studies over the last 50 years. "Over the course of 50 years, sperm concentration has fallen about 50% around the world," said senior study author Melissa Perry. "While there are likely many more contributing causes, our study demonstrates a strong association between two common insecticides "organophosphates and N-methyl carbamates " and the decline of sperm concentration." Organophosphates are the main components of nerve gas, herbicides, pesticides and insecticides and are also used to create plastics and solvents. They are widely used in agriculture on the crops we eat. We use them in structural applications within homes and buildings. N-methyl carbamates are structurally and operationally similar to organophosphates, killing insects by damaging their brains and nervous systems. The study, published ... in the journal Environmental Health Perspectives, examined 25 studies around the world on the two chemicals. Those studies looked at 42 different levels of impact among 1,774 men in 21 different study populations. Men who were more highly exposed to the pesticides, such as those who work in agriculture, had significantly less sperm concentration than men who had the least exposure to organophosphates and N-methyl carbamates, the study found.