Our parents and grandparents form part of who we are. They reared us and served as our role models, and they also passed on their genes. That’s why we are similar to them, and why we share a genetic predisposition to develop certain diseases. Yet genes may not be the only molecular factors we inherited from them. The effects of the lifestyle and experiences of previous generations—including how well they ate and whether they suffered emotional trauma—can also be passed down through the generations via biochemical markers in sperm and egg cells.