This is ripe for a lawsuit.
Will anyone discriminate on the basis of employees indulging in promiscuous homosexual sex? That is a major driver of bad health for people. There are other areas too, which if we are to be intellectually honest, need to be looked at, if the goal is optimal health for employees.
It has already been litigated and the smoker lost.
It turns out that employers have an interest in hiring people who have fewer sick days, lower insurance costs, and no smoke breaks. Smoking stinks, the smell affects people with allergies, and it a major turn off for many customers and clients.
Smoking is a voluntary choice, and no one owes anyone else a job when they make choices that will almost certainly negatively affect the employer. I quit nearly 12 years ago, and would not have ever thought to demand to be put on equal footing with a non-smoker in the job market.
http://usatoday30.usatoday.com/money/industries/health/story/2012-01-03/health-care-jobs-no-smoking/52394782/1
http://bizactions.com/pop_artsam.cfm?id=1091,751&type=2