One of the main festivals of the Buddhist calendar is this week and it's called the Lha Bab Duchen - the festival of the Buddha's descent from heaven.
In a way it's like a second coming of the Buddha. He comes back from heaven where he went, during his life, to teach the Dharma to his mother for three months.
His mother had died one week after his birth and he had been brought up by his mother's sister who married his father and was therefore his step-mother.
However, he owed his birth and we owe his birth to his mother, Queen Maya. He was repaying her his great debt to her as his mother. This is a very important Buddhist sentiment, both the repaying of a kindness in general and in particular of repaying the kindness of one's mother, indeed of both of one's parents and all those who care for us and teach us how to live.
In the Buddhist view of the Universe none of our relationships are arbitrary or meaningless and we owe most to those from whom we receive most.