You can get it here..
It's the official symbol of the American Atheists Organization
Ok...the double helix, invisible pink unicorn, evolve fish, flying spaghetti monster, happy humanist, and the new elegant "A" symbol are all available at http://evolvefish.com/fish/jewelry.html
I'd get me the double helix in a heart beat if it weren't solid frekkin' gold! If anyone sees an empty Darwin fish pendant that actually resembles the stylized car emblem version, please share!
My parents did the same thing when i had a "Fight Racism" bumper sticker on my car. They wanted me to be quiet and nondescript because the KKK was founded just one county away and there were a lot of racists in our area. However when i brought home a girlfriend from India one day they freaked and i knew the reason why. It contrasted with their worldview as they were against interracial relationships.
Wearing a pendant doesn't make you an activist. It gives off a notice that "this is how i feel and i am proud of that". It's a part of who you are. I have told many people in my sleepy dead end hometown that i am atheist and not once has anyone wanted to fight me or threaten me because of that.
I think they're afraid of it becoming public knowledge you are atheist and how they will have to hear people saying bad things about you and casting judgement on them thinking they are bad parents because you're no longer indoctrinated.