The word “testis” dates from the Latin meaning to bear witness. In ancient Rome, only men could bear witness or testify in a public forum. In order to show importance to their testimony, they would hold their testicles as they spoke, and an oath was declared while holding another testicles. THIS FACT NEEDS TO BE RESEARCHED. It seems that word testis derives from word testificare ‘to bear witness’ and there is very little data to support original idea of holding testicles. However, in book of Genesis there are passages in which a man who is taking an oath puts his hand “under the thigh”.