Why does a child look more like its father than its mother, or vice-versa?
(Please help me find as many websites as possible to help answer this question. This is a huge project and I really don't know where to start.)
Basically, after fertilization of a sperm and an egg nuclei, the genetic component of the child has been determined, equally by each parent. However, someone may resemble one parent over the other due to the fact that some traits are dominant and are expressed in the phenotype of the offspring and some are hidden because they are recessive. This principle of dominance was determined by Gregor Mendel, whose work with pea plants started the field of genetics. Also, besides dominant and recessive genes determining traits, there are also polygenic traits. These are produced by the combined effects of many genes and also the environment plays a role in how these genes are expressed. An example in people is height and skin color. The child might not necessarily reflect the skin or height of either parent as several genes are contributing to the phenotypic effect. Therefore, how we look is a combination of many factors including genetics and environment.