Any gentleman may have friends who do not drink alcohol. Whatever the reason for that choice - religious belief, addiction, or other health concerns - a gentleman respects it. He does not pressure anyone to drink; neither does he ask probing questions. When he is serving as a host, in his own home or a restaurant, he makes certain that his non-drinking friends have plenty of appealing nonalcoholic options.
If a gentleman chooses not to drink alcohol, he does not impose that decision on other people. If he is offered a cocktail, he may say, "Thanks, but I don't drink alcohol. I'd like a soda or some sparkling water - whatever you have handy." He offers no further explanation.
-How To Be A Gentleman (Revised and Expanded): A Timely Guide To Timeless Manners