Here is a talk by Mark Lynas, an activist heavily involved in the campaign against GM crops.
He changed his mind! And speaks about his journey. It is a great summary of issues behind GM crops.
If you prefer a transcript to read in your spare time, you can get it [here](http://www.marklynas.org/2013/01/lecture-to-oxford-farming- conference-3-january-2013/), also in German, Spanish, French, Vietnamese and Italian! As you may expect there are lots of comments too.