The concept of heredity is that genes are not randomly passed down. Well, technically they are but we use punett squares to predict the chances of passing certain traits. Because virtually all traits that are dominant are more common than recessive ones, and because all genes are not passed in a completely random way, it is not just pure chance, but calculated chance by which we can predict the probability of what genes are passed down. Hope this helps!
There is a probability of any trait in an offspring. Based on the genetic makeup of the parents, the chances of obtaining certain traits in a child can be calculated. Simple calculations include using punnet squares, for simple dominant recessive traits.
