A review of recent research found that "you also can inherit ways in which regulation of her (mother's) genes has been altered by experience and the environment. Such influences can freeze the on-off switch for some gene in one position. Moreover, environmental influences can permanently silence genes, either by destroying transcription factors that activate them or, indirectly, through these still-mysterious micro-RNAs.
In other words, while environment rarely changes the DNA sequence of a gene (i.e., a "mutation"), it can cause epigenetic changes in the gene's regulation. And if that occurs in an egg, such epigenetic markers can be passed to offspring, resulting in "nongenetic transmission of traits." There can be mother-to-child nongenetic transmission of traits related to the normal workings of the body, behavior and propensities toward certain diseases...."
But that is not all!
Older theories held that "epigenetic markers appeared to be erased in sperm, precluding them from transmitting anything except genes. Naturally, this is turning out to be wrong...stressful upbringing caused epigenetic changes (due to those micro-RNAs) in sperm...(research in mice) demonstrates further how the environment can alter biology with multigenerational influences. But more specifically, sperm, and the lifestyles of the organisms that make them, play a larger role in these processes than previously thought."
For the full review article and citations see:
So, extending these beginning research findings, if we needed it, we may someday find scientific evidence which clarifies how even our biological inheritance includes the karmic activity of our ancestors and those they interact with.