The Kruc Study In 1968, Professor Joseph Kruc, a member of Purdue University’s department of biochemistry conducted a study of Stevia at the University of the Republic in Montevideo. Giving a small number of rats very high doses of stevia, it was concluded that the rats given the herbal extract produced less offspring than those who were not. The problem, even Kruc admits today, is that the rats in the study were given such high doses of Stevia for such a short period of time that, even if it did cause the fertility problems noted, it could have been because of an overdose of the compound. People ingesting Stevia as a sweetener would never be able to consume such a large amount in such a short period of time. Another concern Kruc admits is that there is no evidence to show that the reaction experienced by the rats would also be experienced by humans.

The Alvarez Study In 1988, professor Mauro Alvarez of Brazil’s University of Maringa Foundation repeated the study, reporting in a Brazilian pharmaceutical journal that female mice given Stevia experienced a contraceptive effect similar to those reported by Kruc. The problem with the results, argue critics is that the Alvarez study lacks the information and analysis required by such a research study and cannot be considered valid. According to the Herb Research Foundation the study lacks any credibility at all and should be disregarded. Even Alvarez himself now claims that further research has led him to believe that Stevia is completely safe for human consumption. Despite the problems with both studies, the FDA continues to use them as their main source against Stevia.

https://natural-fertility-info.com/does-stevia-cause-infertility.html#:~:text=In%20short%20it%20seems%20that,be%20used%20for%20contraceptive%20purposes.

It seems that the real conspiracy was to keep Stevia off the market, in favor of artificial sweeteners, such as saccharine, aspartame etc.