Origin of myths
Not hard to be that the origin of myth is caused by beliefs people have about life. So, according to this we may state that first myth about life appeared as the humanity start its cognising of the world. There were and are facts, events and phenomena that surround people and those are of great interest for them. It is hard for people to live next to something they can't explain. There are phenomena that occur in everyday life of people and those phenomena strike humans' imagination with their beauty, danger or origin.
People are creatures of curious nature and so they always wonder about how this and that operates. Though, they were not able to give reasonable explanation for the phenomena and they explained those on their own way. That is how the myths appeared. Those are may be considered as explanation myths. Such name is caused with the nature and function of myths. The explanation myths are created as an attempt to explain things that surround us. Those myths are easy to be vanished as with appearance of science reasonable explanations were given for everything.
There are also myths created in order to emphasise significance of one or another event or thing. Such myths are created unconsciously by people who are admired with something. For example there is a myth about penny-killer. People who believe in this myth state that a penny fallen down a high make a speed enough to kill one or to stick into pavement. Usually, the high enough for that is a high of Eiffel tower. So, people who are admired with the majesty of this architecture masterpiece created such myth in order to emphasise the high of Eiffel tower.
Though those myths are well-intentioned they can't be considered as true myths. One may admire with keen of mind of a person who created those though may can't believe in the myths. It is better to know for sure what is real and what is not. Such disbeliefs may result in a number of misunderstandings that will be passed on from one generation to another and so will result in false vision of world. It is okay to use some fairy-tales when you try to explain something to a child, though you should know when it is enough to suggest such tales to them.
Let you and your child know how the real world is look like. Let them know what is wrong and what is false, don't confuse them with fiction they will believe in. such fictions may cause the contradictions of beliefs you suggested to your child and beliefs suggested him or her by teachers. The myths parents create for their children are also explanatory myth and those are of great use for parents. Though, it is important to know when it is a high time to explode the myth and show the real life for a child. And, may be it is high time for you to open your eyes.