Its one of those issues everyone seems to take a side on.
Are e-cigarettes reducing the harm done by cigarette smoking....or do they present a new, potentially attractive route for a younger generation to get hooked on nicotine.
For the uninitiated, electronic cigarettes involve a device that heats up a vapour containing nicotine - but which does not contain the harmful ingredients of tobacco.
Latest figures suggest two million people use them.
Today we got details of new research that could worry parents in particular - it raises the disturbing question: are teenagers trying e-cigs as a trendy novelty?
In a survey of more than 16,000 14-17 years in Northwest England, 19% said they had tried or purchased e-cigarettes.
Of the teenagers that had tried e-cigarettes, 16% had never smoked before while 23% had tried smoking but did not like it.
The e-cigarette industry says this survey shows teens experimenting as a ‘one-off - but no there are no signs of them becoming on-going users.
I spoke to Professor Robert West, a leading authority on e-cigarette use, and he too believes the new figures should not be seen as particularly worrying.
There is a currently a voluntary ban on sales of the products to under-18s and that is expected to become legally enforceable in the near future.
Whether e-cigarettes are an escape route from smoking, or for some a gateway to nicotine, will continue to be a debate that strongly divides opinion.