How long before genetic sequencing is able to tell us exactly how our children will look and act?
Genetic sequencing will never be able to perfectly predict an organism's appearance and behavior for the simple reason that genes are not the only thing that determine biology. There are three basic factors that determine the nature of an organism: 1) genetics, 2) unconscious environmental factors, 3) learned and conscious behavior. Your genes only directly determine basic biological properties such as the number of eyes, the shape of bones, and gender. Your genes do not determine exactly where every mole will grow, how obese you will be, or which baseball team you will route for. The textbook Developmental Biology by Russ Hodge states, "Development is constantly influenced by subtle events in the environment, and many of an organism's features are not determined by genes. For example, every human embryo is programmed to develop fingerprints, but the precise patterns they form are determined by tiny, random events that vary from individual to individual."