Stereochemistry was important in solving the thalidomide disaster in the 1960s. Thalidomide is a drug that was first produced in 1957 in Germany. Doctors used it to treat morning sickness in pregnant women. Later, the drug was shown to cause deformations in babies. One isomer of the drug was not dangerous, but the other caused serious genetic damage to the embryos. In the human body, thalidomide undergoes racemization: even if only one of the two stereoisomers enters a human body, the body changes some of it to other one. The thalidomide disaster caused governments to test drugs more carefully. Selected people take new drugs in an experiment (clinical trial) first before the drug is made available for public use. Thalidomide is now used as a therapy for leprosy. Women must use it with contraceptives to prevent pregnancy.