Why is my brother/sister different from me?
There are a lot of factors that influences how you and your brother or sister looks like and one among them is the biological factor. There is something called genes, which is acquired from both our mother and father. Each gene can represent different characteristics traits of a person and the physical appearance. Some behavior and habits might also be influenced by genetic factors.
For example, you may be a good singer or dancer, which you got from your mom; likewise you have the habit of sleeping in a particular position like your dad. Few children resemble completely like their father or mother in terms of physical appearance; and few may not be completely like your dad or mom; they can have mixed features from our parents.
In the same way, you and your brother or sister may not be the same completely. What you don’t have from your mom, your brother or sister can have it and what you have from your dad, your brother or sister could not have it. These aspects are totally determined by the genes you received from both your mom and dad.