Fatherhood in America has changed considerably over the past two centuries, as has the very definition of manhood. It was in the early 19th century that “a new ‘domestic’ family type that altered the cultural meaning of being a father” emerged, Shawn Johansen wrote in his "Family Men: Middle-Class Fatherhood in Industrializing America" (Routledge, 2001), the beginnings of what has been commonly viewed as the decline of the American patriarch. This shift in power in middle-class families continued through the Victorian era, according to Johansen, with fathers of the late 19th century significantly more involved with their children than popularly believed.
Through much of the 20th century, much pressure was put on fathers to commit to the responsibilities of parenting, something not the case with mothers. It was assumed women would naturally take to their role as mothers, in other words, simply part of their nurturing instincts. Dads were consistently urged to spend time and get to know their children (particularly their sons), with parenting presented as a rewarding complement to careers and personal time. Fathers were thus faced with a tricky balancing act, real or imaginary, in which they were expected to devote considerable amounts of time and energy to child raising without abandoning their principal role as family breadwinner. The tensions associated with walking this fine line could be detected in various ways, as men struggled with the different hats they were being counted on to wear. American dads are now in a good place in this respect, I believe (when they are present, of course), embracing both the joys and demands of fatherhood on their own terms.