In most instances smoking becomes a critical issue when the parenting skills of the parties are equal and the court is searching for factors that may tip the scales in deciding custody. Some courts, however, have given limited weight to the issue holding that smoking "should in no way be construed as reflecting negatively on petitioner's ability to parent the children." In Helm v. Helm, 1993 WL 21983 at *1 (Tenn. App. 1993).

A Tennessee Court of Appeals ruled that "[i]deally, no child should be exposed to cigarette smoke in any degree. It must be given some consideration in the selection of a custodian for the child. However, it is one of many factors to be considered, and is not necessarily the dominant or decisive consideration."

In Heck v. Reed, 529 N.W.2d 155 (N.D. 1995), the court found that the mother smoking in the presence of an asthmatic child did not rebut the presumption against awarding custody of the children to the defendant-father. Although the mother's smoking was restricted, she retained custody despite the evidence that she was harming the child through ETS. As stated by the court, "we do not believe that the legislature intended that the presumption against awarding custody of children to a perpetrator of domestic violence be trumped by the fact that the victim-parent smokes." On the contrary, exposure to ETS has been held to override the preference of the child in custody cases.