There is less predestination than we expect. We can change our destinies in many ways - big and small. Starting with flipping a coin and ending with choosing a wife. Having or not having a kid or kids could start a lot of causual chains.
Important part - not to go crazy. And not to become too ridgid. Predestination could be fixed patern of reactions in given circumstances.
For editor: I am Alex Dimond. firstname.lastname@example.org