His parents met around what could be considered the dark ages for the ponies I guess, his mother was out in a field collecting some wild herbs and his father happened to be wandering the edge of the woods along the field. She (his mother) saw movement in the tree line and her curiosity drew her to him (his father). As she was getting closer she tripped over his tail and fell, dropping her basket and supplies.
He was startled at the sudden contact from someone because he hadn't been touched by a living creature in a very long time. The dragon had been banished from the dragon lands because he thought it was wrong to be pillaging pony towns like the others were. He helped the mare up and they talked for hours until they both realized the sun was setting. they agreed to meet the next day and the day after that and so on until they eventually fell in love and moved into a cottage in the forest where they first met.