One evening, after watching Homer Simpson wreck the family car at a monster-truck rally and plunge on a skateboard into Springfield Gorge, my 6-year-old son asked me, "Why are dads on TV so dumb?" Having grown up with the omniscient fathers on "Leave It to Beaver" and "My Three Sons," I wanted to give a bemused yet authoritative answer, chuckling wisely as I explained the ways of the world. But this question left me feeling more like Homer Simpson. Where did we fathers go wrong? We spend twice as much time with our kids as we did two decades ago,...