Our ancestors\' lifestyles could be linked to today\'s obesity and diabetes. The lives lived by grandparents can directly affect the lives of future generations, and the health patterns of grandparents are now known to be passed on through both the mother's and the father's genes. Sperm do more than deliver a father\'s DNA to an egg. They also carry messenger RNAs - the molecules that carry out the instructions of a paternal gene - to the egg at fertilization. Stephen Krawetz of Wayne State University School of Medicine, Detroit , and colleagues also found micro RNAs, which bind to sites in target messenger RNA to regulate how they are used. These RNAs may also alter the way genes are used over generations, perhaps in response to a crisis such as starvation.