What are some tips for boys and girls? Boys and girls are the most basic distinction in human society, and how to distinguish boys and girls is a relatively easy problem. Traditionally, we use physiological characteristics to make distinctions, but this method only applies to actual contact situations. Modern non-invasive evaluation technology provides a more effective and safer evaluation method. Below we will talk about some non-invasive ways to see boys and girls from four aspects: appearance, language, behavior and emotion.