There are thousands of studies showing harm from GMOs and related pesticides/herbicides since the introduction of GMOs into our food supply 18 years ago.
They can be found at:
Vandana Shiva on how Billions are starving because of GMOs on BBC:
GMO Myths and Truths by www.earthopensource.org
Deepak Chopra speaks about GMOS on Outside the Box with Jason Liosatos
Zen Honeycutt of Mosm Across America about GMOs and Glyphosate with Jason Liosatos of Outside the Box
Shop with Zen in a health food store and look at what we need to look for and avoid in our foods when GMOs are not labeled. It's not always clear.