In November 1960 a German pharmacist wrote Grünenthal a letter asking if Thalidomide could cause malformations in unborn babies.
On December 2, 1960 Grünenthal responded to the pharmacist denying any damaging effect on fetuses. Grünenthal had no evidence to back this answer up. Thalidomide had never been tested on pregnant women or pregnant animals.
Sources: Chronology of events provided by Beate Kirk, in: Der Conterganfall: eine unvermeidbare Arzneimittelkatastrophe? Dissertation. Greifswald 1998.