From the American Academy of Pediatrics:

"Marijuana currently is classified by the US Drug Enforcement Agency as a schedule I drug, which means that it has a high potential for abuse, has no currently accepted medical use in the United States, and lacks accepted safety for use under supervision by a physician. Rigorous scientific research to deter- mine whether marijuana, especially cannabinoids, has any potential therapeutic effect is just beginning. In contrast, the significant neuropharmacologic, cog- native, behavioral, and somatic consequences of acute and long-term marijuana use are well known and include negative effects on short-term memory, concentration, attention span, motivation, and prob- lem solving, which clearly interfere with learning; adverse effects on coordination, judgment, reaction time, and tracking ability, which contribute substantially to unintentional deaths and injuries among adolescents (especially those associated with motor vehicles); and negative health effects with repeated use similar to effects seen with smoking tobacco."

Smoke if you like, but don't push it on the rest of us or our children.