What are some pros and cons of labeling genetically modified foods?
The obvious effect of labelling genetically modified food is that consumers know it's modified, and some people might change their consumption habits accordingly.
If people believe that genetically modifed food is bad for the earth or has some negative health consequences associated with it, they would be less likely to purchase or eat it.
If they don't care, they might be more inclined to consume it because mono-crops produced in bulk (which is what genetic modification of organisms enables) are the cheapest possible option at grocery stores.
I will point out that around 70% of food available in American grocery stores is genetically modified and it's not labelled - so you eat it, and so does everyone else, whether you think you do or not.