Child custody lawyers know that they can never guarantee the outcome of any disputed custody case. Winning a child custody case is never predictable. All manner of factors influence custody decisions. Smoking, school districts, athletics, religious differences, ages of the children -- all can be factors influencing a judge's decision about the best interest of the children. Lawyers who have appeared before a judge many times may have some idea about how he or she thinks; none, however, can guarantee a result. The phrase the best interest of the child is content neutral; it does not -- it cannot -- be defined in advance for any specific case. Judges have a great deal of latitude interpreting what this phrase means in a given case.

For example, smoking sometimes becomes a consideration in determining the terms and conditions of custody and visitation. In recent years, in cases where one party raises the issue, courts have shown a willingness to make the tobacco use by one parent a consideration in the terms and conditions of custody and visitation, usually in cases where one parent smokes and the other does not.

In 1994 a Florida appellate court ruled that circumstances "may well exist" where a child in "a smoking environment...may not be in the best interest of the child." In this case, Thomas v. Harris, the child had special health considerations, and the ruling recognized that "the effects of second-hand smoke can be a valid consideration in a custody determination." Other cases in New York and New Jersey have reflected this consideration.