After years of thinking he'd never have kids, Lee Gutkind became a father at forty-seven and, following his divorce, soon found himself taking over more and more of the primary care responsibilities for his son, Sam. As one of a growing number of "old new dads" (recent studies have shown that one in ten children are born to fathers over forty), Gutkind realized that he faced challenges--both mental and physical--not faced by younger dads, not the...