People look different, act different and like different things. Everyone is different. Different does not mean better or worse. It just means different. Some differences are easy to see, and some are not. Human DNA is more than 99.9% the same from person to person. The 0.1% that differs comes from variations among about 3 billion DNA “letters.” Even within one family, people can have different blood groups and eye colors, because their DNA differs a little.

Eye color is different from person to person, from very light blue to dark brown. Fingerprint ridges on every finger of every human being are unique. They do not change as a person grows or ages. Most people are right-handed. About 1 in 10 people (10.6%) is left-handed. About 9% of people use different hands for different tasks. That share is almost as big as the share of left-handers. Hair can be different colors, lengths and styles. Some people are taller or shorter than others.

A disability is a difference that makes it harder for someone to do something that others can do easily. Having a disability does not mean a person is sad or cannot do things for themselves. Some disabilities are visible and some are not, so you cannot always tell by looking at someone. Some people use a wheelchair to get from place to place. In 1975, U.S. public schools accommodated only 1 out of 5 children with disabilities. Many states had laws that explicitly excluded some of them, such as children who were deaf or blind.

Louis Braille was blinded at the age of three. He invented the braille system in 1824 as a student at a school for blind children in Paris. Braille is a system of raised dots that people who are blind or have low vision read with their fingers. American Sign Language (ASL) is a complete, natural language with the same linguistic properties as spoken languages. Its grammar differs from English. The first Paralympic Games took place in Rome, Italy, in 1960, with 400 athletes from 23 countries. They have been held every four years since.

Families come in all different shapes and sizes. Sometimes a grandparent, an aunt or an uncle takes care of a child. Some families have stepparents, one parent, or parents who found their children through adoption. People like different things, and that is okay. A pre-K or kindergarten student may not be able to explain it. Even so, young children are often put off by differences. This reaction is common and normal. Meeting people who are different makes them seem less strange.

Young children usually ask direct questions about differences out of curiosity, not to be mean. When a child asks about a difference, a simple and honest answer is best. Staring, pointing and leaving someone out are unkind. A respectful question is fine. Empathy is the ability to sense other people’s emotions. It is also the ability to imagine what someone else might be thinking or feeling. Perspective taking is the ability to identify and understand other people's emotions. It is a skill that keeps developing through adolescence.

Almost all kids are kind to somebody. The real work is getting kids to be kind to people outside their immediate circle of concern, says Harvard researcher Richard Weissbourd. Friends, or peers, are people your age or close to it who have experiences and interests similar to yours. Cliques have set rules about who is “in” and who is “out” and are focused on status. Groups of friends let kids hang out with many other people. Kids with self-esteem feel liked, accepted and confident, and they feel proud of what they can do.

Treating someone badly because they are different is not okay. Kids who bully sometimes pick on someone who looks or acts different. This is never okay. When teasing becomes hurtful, unkind and constant, it crosses the line into bullying. Leaving someone out on purpose can be a kind of bullying. If you see someone being picked on, you can stand up for them or tell an adult you trust. A grown-up you trust can help when someone is being unkind. A grown-up you trust can help when being different feels hard. A grown-up you trust can help.

Words to know

• disability: harder task
• empathy: feeling for others
• peers: people your age
• cliques: closed groups