Although many factors influence the size of a family, Australian researchers have found that the genetic influences on both the number of children you have and the number of grandchildren you have are identical.
This suggests that the genes affecting the number of kids you have are the same as those which affect how many grandchildren you end up with.
Previous measures of reproductive fitness considered only the quantity of offspring, possibly neglecting variation in offspring reproductive quality that may influence the number of grandchildren.
Read the full, original story: How Many Children Do You Want? Your Genes May Get The Final Say