Here are some good papers -

http://www.sciencedirect.com/science/article/pii/B9780444593894000021

http://www.sciencedirect.com/science/article/pii/S0956713506000107

RETRACTED: Long term toxicity of a Roundup herbicide and a Roundup-tolerant genetically modified maize

Gilles-Eric Séralinia, , , Emilie Claira, Robin Mesnagea, Steeve Gressa, Nicolas Defargea, Manuela Malatestab, Didier Hennequinc, Joël Spiroux de Vendômoisa

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doi:10.1016/j.fct.2012.08.005

http://www.i-sis.org.uk/Elsevier_Climb_Down_over_Seralini_Retraction.php

Sounds about right!  No good evidence-based study that shows harm.

I would agree that no science based risk assessment has shown harm in realistic situations.  However, there is a nuance which it is important.  Most, if not all, national authorities have a system in place to ensure a science based risk assessment takes place (which takes into account environmental safety and human food/ animal feed issues) before an approval is given for commercial use. Certainly, this is the case for all agricultural uses for GM crops. And here comes the nuance which is really important to understand. Plenty of authorities have given approvals for specfic uses of a specfic crop with a specific modification.  No regulatory authority considers whether or not GMOs are harmful in the abstract. It is always undertaken on a case-by-case basis for a specific application. Given the current national regulatory systems, it makes no sense to consider whether or not GMOs in general are harmful or not. 

I'm a student like you so take what I suggest with a pinch of salt. Any harm would likely come at a molecular level. If I were looking to find data I would be looking at how the digestive system and liver breaks down any modified material. I'd also look at if there are novel chemicals that modify the immune response or that the detox pathways cannot deal with.

I haven't yet seen anything conclusive but fully expect to over time.