When the product should not be used ACCORDING TO HEALTH CANADA - AND THAT INCLUDES FOR MEDICAL PURPOSES 

Cannabis should not be used if you:

are under the age of 25
are allergic to any cannabinoid or to smoke
have serious liver, kidney, heart or lung disease
have a personal or family history of serious mental disorders such as schizophrenia, psychosis, depression, or bipolar disorder
are pregnant, are planning to get pregnant, or are breast-feeding
are a man who wishes to start a family
have a history of alcohol or drug abuse or substance dependence
Talk to your health care practitioner if you have any of these conditions. There may be other conditions where this product should not be used, but which are unknown due to limited scientific information.

NO MAN SHOULD USE MARIJUANA IF HE WISHES TO START A FAMILY DUE TO THE RISK OF TESTICULAR CANCER, DNA DAMAGE, SPERM MORPHOLOGY, AND STERILITY AND THESE SCIENTIFIC FINDINGS ARE ACKNOWLEDGED BY YOUR GOVERNMENT - WHO ALSO WANT TO LEGALIZE