As always, we should take new theories with a grain of salt. In this case, you might get a little grossed out!
The Toxoplasma gondii parasite is carried by felines (cats) and has be found to infect their human masters too. The parasite can be caught through contact with the animals and their bodily fluids and solids. The parasite causes brain cysts that last a lifetime and lead to behaviors including bipolar disorder, reduced fear, and lower IQ.
Some have estimated that over 2 billion humans have been infected, though infection rates differ greatly by country. For instance, the U.S. infection rate is around 3%, while it may be as high as 50 to 70% in France and Mexico. Petr Houdek at University of Economics in Prague reviewed the literature in a 2017 paper published in the Academy of Management Perspectives.
New research by Stefanie Johnson (Leeds School of Business) and colleagues (a gang of non-biologists) suggests that those infected by the virus are 1.7 times more likely to choose entrepreneurial career paths. They test subjects for infection by taking saliva swabs. They find significant positive associations between infection and entrepreneurial activity and intention, and a significant negative association with fear of failure.
This research is pretty new and should be replicated several times before budding entrepreneurs decide to expose themselves voluntarily.
Risky business: linking Toxoplasma gondii infection and entrepreneurship behaviours across individuals and countries Stefanie K. Johnson, Markus A. Fitza, Daniel A. Lerner, Dana M. Calhoun, Marissa A. Beldon, Elsa T. Chan, Pieter T. J. Johnson Proceedings of the British Royal Society B, Volume 285, issue 1883