Psyringe
Scout
That is why it is an optional feature. Along with random personalities.
And I'm glad it's in as a feature. I just wonder whether it could be improved.
For example, would anyone object to a rule like "You can't trade techs away that you didn't research yourself until you've had that tech for x turns", with x = 50 (preferably changeable in an XML file)?
Or something like this: "You can't trade techs away that you didn't research yourself, but if you research any tech yourself, then all techs that lead to it become tradeable"?
Both alternatives would imho feel less artificial than a simple inability to ever trade such techs, while retaining the spirit of the simpler rule. (It might be that it's already implemented this way, the information about this option is rather scarce right now.)