I keep seeing people repeat this, yet I can't find any information to confirm it. you can become a German citizen and still retain your US citizenship, from everything I've read and everyone I've asked on the matter.
IANAL.
[0] http://www.gesetze-im-internet.de/rustag/__10.html [1] https://en.wikipedia.org/wiki/German_nationality_law#Natural... [2] http://www.gesetze-im-internet.de/rustag/__12.html
There are a few other rare exceptions. But it is completely impossible under the standard naturalization process, which requires you to renounce any previous citizenship.