It may surprise many parents to learn this, but it is possible that your child learned that there is a difference between boys and girls as early as 18 months. In fact, by the time most children are around two years old, they will begin to identify more with their own gender, and this will continue to develop until around the age of six. This is when you will begin to notice that your child is exhibiting typical behaviour of his or her gender, and while there is an external influence of some kind, it is a combination of nature and nurture that causes your child to identify with being a girl or a boy – so some of it is out of your hands!
For most of their childhood, and even into their early teens, girls and boys will grow physically at around the same pace. These changes during the preteen and early teen stage, when girls may suddenly become a lot taller than their male peers, but a few years later, the boys in their classes will catch up, and pass them by in terms of height.
Boys tend to be more aggressive and impulsive, and their gross motor skills, including walking, running and jumping, tend to develop slightly faster than girls do.
Girls, on the other hand, are usually more reserved (proven by studies of brain activity) and while they lag slightly in terms of gross motor skills development, they tend to develop fine motor skills, like drawing and picking up small objects faster than their male peers do.
Girls are also better at communication, even at an early age, and tend to talk earlier, and have better vocabularies than boys. They also tend to potty train faster than boys of the same age group do.