"Among our cohort of children presented here [in this study], however, the majority of the parents were not known to be using illicit substances themselves and, on the basis of our clinical assessments, appear to be able to parent their children adequately. It is not likely that the production of drugs, particularly marijuana, hinders effective parenting much more than actual drug use, yet the differences in the ways these cases are handled suggest that police and child protection agencies perceive the former to be of greater concern with respect to child safety than the latter."

Source

Moller, Monique; Koren, Gideon; Karaskov, Tatyana; and Garcia-Bournissen, Facundo, "Examining the Health and Drug Exposures among Canadian Children Residing in Drug-Producing Homes," The Journal of Pediatrics (Cincinnati, OH: July 2011), p. 4.
http://www.ncbi.nlm.nih.gov/p…