From the book "33 things to explain the world to kids".
You have a first name and a second or last name and maybe a middle name too. Your first name, or the name by which you are called, was chosen by your parents. Your last name shows the family you belong to – usually it is the same last name your mom and/or dad carry. Besides making you identifiable, a last name shows who your ancestors are. For a lot of people the family they come from is a very important part of who they are – their identity. And in many cultures around the world your family heritage, shown by your last name, is still important to be granted a certain rank in society.
But family means more than sharing a last name and a history. There are many different forms of family: moms and dads, step-parents or grand-parents, living together with their children and grand-children. Other family members may live in the same house or elsewhere: like half-brothers and sisters, aunts, uncles or cousins. A family lives together to share a home and food as well as financial and emotional support; and it has legal rights and obligations with respect to other family members.
Family is about love and commitment. A family shares good and bad, cares for and supports one another, and provides the values and beliefs that you will carry with you into adulthood. Your family knows you better than anyone else--at least during your childhood years!
As you grow older, your very close friends can also feel like family. Eventually, you may fall in love and decide to start your own family. You may no longer live with your mom, dad, brothers or sisters--but they will always be your family for the rest of your life. They are part of your identity, in a scientific sense as well as by the knowledge and values they pass on to you.
Your name says where you come from. But who you are and who you become in life are shaped by how you are raised, how you are loved, and how you love.