I found this reflection from Lev Grossman (author of The Magicians, among other things) quite intriguing. It's an extract from a reflective piece on how fatherhood changed his life and rerouted his writing.
In my case, becoming a father certainly changed my life. Curiously, I sent the manuscript of The Raven's Seal to my publisher just days before my son was born, and the fractured time outside looking after him as a baby was devoted to preparing The Raven's Seal for publication. Something about the urgency of both circumstances, I think, helped me focus.
But I do believe, like Grossman, that a wider sense of family and human relationships are important for a writer. And that writing plans need to be disturbed, even demolished sometimes, so that we can turn to what is really important, in living and writing.