There is a short animated sequence to be found at Inheritance of Acquired Characteristics [Animation] which shows how a warm and nurturing style of mothering by a mouse removes brain ‘markers’ which might otherwise lead to the young growing into fearful and anxiety-ridden adults, the females likely tending to pass on those traits to their young in turn. I would imagine that in any species where the fathers play an active role there would also be a paternal effect on the young as well.
In this lead-in to an article to be published in the December, 2011 issue of Scientific American, Epigenetics Offers New Clues to Mental Illness [Preview], we learn:
Experience may contribute to mental illness in a surprising way: by causing “epigenetic” changes—ones that turn genes on or off without altering the genes themselves.
We are individuals who are truly members of family lines. What our parents, especially our mothers, experience and how they respond to it, what we experience and how we respond to it, shape us, make us into different human organisms that we would have been with different experiences or different responses. As we learn more about the world and about us in particular, we seem to be more complex and also more fully embodied, for good and bad.