According to the Buddha’s teaching the beginning of the life-stream of living beings is unthinkable. THe believer in the creation of life by God may be astonished at this reply. But if you were to ask him ‘What is the beginning of God?’ he would answer without hesitation ‘God has no beginning’, and he is not astonished at his own reply.
Walpola Rahula, What the Buddha Taught: Revised and Expanded Edition with Texts from Suttas and Dhammapada