[hiphopyo]

You're absolutely right -- everything turns to poison in excess.

Fun fact about THC though: "[...] babies of women who used cannabis at least once per week before and throughout pregnancy were 216 g lighter than those of non-users, had significantly shorter birth lengths and smaller head circumferences."

http://www.ncbi.nlm.nih.gov/pubmed/11843371

[jp555]

That's still more hypothesis, not conclusion. "Self-completed questionnaire on use of cannabis before and during pregnancy." = Observational study = result can ONLY be a hypothesis.

It's right there in the conclusion "may be associated" = "they do not know if this is true at all".

Next step would be to run a double-blind clinical trial, and have an unknown-half of the subjects smoke pot and compare that to the control to test if their hypothesis is true or not. Until then, it's only conjecture.