Women who were exposed to the pesticide DDT while in the womb had more difficulties getting pregnant as adults than did those who had no exposure, according to a new study published in the British medical journal Lancet. “This is the first research that shows it is possible that these exposures can cause problems 30 years down the line,” said lead researcher Barbara Cohn, an epidemiologist at the University of California at Berkeley’s Public Health Institute. The U.S. banned DDT in 1972, after many years of campaigning by environmentalists and health advocates who said the chemical killed birds and other wildlife and harmed humans. However, some nations in Africa, Asia, and South America still use the pesticide, often to fight malaria-carrying mosquitoes. This new study bolsters some scientists’ beliefs that fetuses and children may be especially vulnerable to environmental chemicals.