I believe there are actually 3 different problems with an assumption they are all caused by the same thing. There are actually problems in the world that aren't the fault of Monsanto.

1. Gluten sensitivity is a specific problem and defined as celiac disease. Very real and apparently there are more people with this problem than originally recognized. Appears to have a lot to do with ones heritage and where in the world your family came from. However that is not the only defining factor.

"Celiac disease is an autoimmune disorder that can occur in genetically predisposed people where the ingestion of gluten leads to damage in the small intestine.  It is estimated to affect 1 in 100 people worldwide.  Two and one-half million Americans are undiagnosed and are at risk for long-term health complications."

http://celiac.org/celiac-disease/what-is-celiac-disease/

2. Using Roundup as a descant/crop dry down, is off label, as it states it will damage germ. I had a customer that said his wheat had been sprayed with Roundup a week before harvest and it really looked good. We asked him to have it germed before spending money having it cleaned. He was surprised as he had a 50% germ. needless he dumped that wheat and got some from elsewhere that hadn't had Roundup used on it.

Gramoxone is the recommended agent for spraying wheat as a desiccation/harvest aid, and it is on label. p5

http://www.cdms.net/LDat/ld77A041.pdf

 3. Problems associated with consumption of grains like wheat. Until rather recently I found this really difficult to accept.  However, there appears to be health problems associated with grain consumption beyond those defined as by celiac disease.

A #1 New York Times bestseller--the devastating truth about the effects of wheat, sugar, and carbs on the brain, with a 4-week plan to achieve optimum health. Renowned neurologist David Perlmutter, MD, blows the lid off a topic that's been buried in medical literature for far too long: carbs are destroying your brain. And not just unhealthy carbs, but even healthyones like whole grains can cause dementia, ADHD, anxiety, chronic headaches, depression, and much more. 

http://www.amazon.com/Grain-Brain-Surprising-Sugar-Your-Killers/dp/031623480X

Research done at Duke University shows effects and determent of a grain based diet and Dr. Westman shares the features of a diet low in grain and carbohydrates . This is a lengthy presentation, an hour +/-.

https://www.youtube.com/watch?v=dSLf4bzAyOM

Have fun