Comment by Staple_Diet

The most compelling evidence of any epigenetic changes influencing offspring were the animal studies that showed trauma to the mother can be evident two generations later in premature maturation of memory systems of male offspring (i.e., grandsons). As you state this is via the maternal line at first, I will need to check if the inbetween carrier was female or male. Rick Richardson has done a lot of work on this, here is one paper but I'd suggest looking at his further work; https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3637360/