The gateway claim is nonsense - research shows that the correlation between earlier marijuana use and later use of other drugs can be explained by a "common-factor" model, that is, a third factor that causes both results, such as individuals' opportunities and unique propensities to use drugs, or mor broadly a social or psychological predisposition towards anti-social behaviour. (http://www.rand.org/pubs/research_briefs/RB6010/index1.html, http://rds.homeoffice.gov.uk/rds/pdfs2/hors253.pdf)
I see I forgot to mention that the same sort of correlation between earlier marijuana and later harder drugs also exists between earlier alcohol and tobacco and later illegal drugs - so if marijuana is a "gateway" so are alcohol and tobacco.
Yes, there are just as many parents who allow teenagers to drink alcohol. Many times, they are the same parents.
Each one of my kids had students in their grade school classes who brought marijuana to school to share and sell, that they had taken from the jar that their parents kept on the Dad’s dresser. The first time it happened, there was one girl bringing alcohol to school and another bringing marijuana and I reported both, not the names, just the fact that it was happening in the girls room. The principal told me that he would do something about the alcohol, but not the marijuana.
What I didn’t explain is that the reason that marijuana is a Gateway is because of parental attitudes, that the marijuana is harmless. You cannot deny that, that is the attitude of marijuana users, and they just don’t take it seriously when their kids start doing it, or selling it to other kids.
When my oldest daughter was in school, it started in sixth grade, when my youngest was in school, their was a fourth grade girl selling the marijuana from her Dad’s stash. That girl’s mother ran for county auditor this year. She would have been in charge of the elections.