Exposure of male and female adolescent rats to cannabis before mating leads to behavioural and molecular abnormalities in their children.  Also affected:  neurotransmitter genes.

See link below.

Epigenetic Effects of Cannabis Exposure

Possible human effects:  schizophrenia, depression, addiction, anxiety and more….

Making studies difficult is the fact that cannabis contains over 60 cannabinoids, which can influence dosage administration and effect of the drug.