When women pick up a baby, 80% of them hold it to their left, instinctively knowing that the baby’s hyperactive right hemisphere–sensing through the right eye and ear–wants their gaze, sound, and connection. This is because babies’ brains are entrained through mirror neurons to wire networks similar to their mothers when connected with gaze, expression, touch, sound, and gesture, and the first two years of life the right hemisphere develops much more robustly than the left. Men who are not fathers, when they pick up an infant, hold it 50%/50% on the right and left. Within weeks of becoming a father, a man holds his baby 80% of the time on the left, and continues to throughout life. Being a father changes you–believe me I know. The week after my son Ethan was born, I went to see Ran at the movie theater, a Japanese remake of King Lear with lots of battles and fights–the kind of movie I loved to see in 1984. I had to walk out after the first battle scene. I kept thinking that all the slain young men were once babies like Ethan. Even though I kept telling myself they were actors and nobody was really killed, I couldn’t stand it. Ethan’s birth had changed me. Fathers are spending more time with their children than any time in the last seventy years. More fathers are stay at home, and more fathers report sacrificing work to be with their children. It’s a good time to be a father.