Something fishy happens when the pesticide DDT gets into eggs—it can transform genetically male fish into apparent females. These altered males are fertile, able to lay eggs that produce young, according to a new study.
"We were really not expecting to see complete [sex] reversal at all," says John S. Ramsdell, a toxicologist from the National Oceanic and Atmospheric Administration (NOAA) in Charleston, S.C. "This is a rather interesting biological observation."
Ramsdell and his colleagues report their results in the March Environmental Health Perspectives.
Sex changes in fish are fairly common (SN: 10/21/95, p. 266: http://www.sciencenews.org/sn_edpik/ls_4.htm), and scientists have known that a type of DDT called o,p'-DDT weakly mimics the sex hormone estrogen and