The argument being made by the CDC, as well as many other anti-smoking groups and advocates, is that electronic cigarettes are a gateway to youth smoking. This is predicated upon a belief that someone who smokes a tobacco or menthol flavored e-cigarette is then apt to try a tobacco cigarette. However, all empirical evidence points to the opposite being the case. More smokers are choosing non-tobacco flavors thereby creating a market for non-tobacco products as opposed to a gateway to tobacco flavors.
Store owners have told TEVA the majority of their customers want non-tobacco flavors. So why would someone who enjoys strawberry want to change to a tobacco flavor? It is akin to trying to getting someone to switch from cherry-cola to black coffee.
For a more complete review of this argument against vaping and its rebuttal we suggest you read Dr. Siegel's blog "Why Electronic Cigarette Flavors Probably Prevent Youth from Taking Up Smoking".