Hair

• Many of the various physical qualities of your hair are influenced by genetic inheritance. Your hair color, for instance, will be strongly correlated with your parent's hair color, as will hair curl, or lack thereof. The thickness of your hair is also genetically inherited. The shape of your hairline, whether you have a widow's peak or a straight hairline, is controlled by just a single gene. For men, baldness is also genetically influenced.
  
  

Facial Features

• There are many different facial features that are influenced by genetic inheritance. Whether or not you have dimples or smooth cheeks is controlled by just a single gene. An ability, or inability, to roll your tongue is also a genetic physical characteristic. The color of your eyes is also influenced by your genetics, as is the kind of earwax you have.
  
  

Skin

• Skin color is, quite obviously, heavily influenced by the skin color of your parents. Certain skin disorders, such as albinism, are also due to genetic inheritance. There are a few other features of your skin, such as a predisposition towards freckles, that are at least partially regulated by your genes.
  
  

Physical Size

• There are also many things about your physical size and physical abilities that are at least partially determined by the genes you get from your parents. Height, for instance, is thought to be heavily influenced by genes, as is obesity and your ability to benefit from a diet. There are many genes that influence your physical abilities, including genes that determine whether you have more fast-twitch or slow-twitch muscles. Fast-twitch muscles make you a good sprinter, while slow-twitch make you a good marathon runner.