|MadSci Network: Genetics|
Wow, this is a more complicated question than you think! Much research has just only begun to answer this question of "looks" and/or physiological processes that contribute to "looks". Although, much of our phenotype is largely based on our genes, so too is our environment. This meaning that there are many attributes of basic development itself that have an effect on how we "look". For example your fingerprints are a random by-product of embryo development not of your genes. So as you can see we get to the basic realization that most involved with evolution and population genetics already know. That is the basic formula of: "Genes plus environment equals phenotype." Remember that phenotype is the physical or behavioral expression of our genes. This is why nutrition and good health of a female while she is pregnant is very important. Lack of nutrients, poor nutrition or excess stress of a female can have irreversible effects on the embryo. Hence fetal alcohol syndrome and other similar diseases. This is not to say that all diseases are due to environmental factors as many are specifically cause by bad genes. However, many things such as "looks" are dictated by the "formula" I mentioned above. Obviously depending on strong or "dominant" and individuals genes are can effect the result of why an offspring may look more like "mom" or "dad". Dot not be upset that there is no clear answer to your question as this is an area of research that has only begun and it shows you are giving a lot of thought to the things that interest you. That's what makes a great scientist! Just remember that the interactions of our genes and the environment is a very important aspect of population and evolutionary studies. Try looking up books and information about developmental biology in combination with evolutionary biology and genetics.
Try the links in the MadSci Library for more information on Genetics.