My wife and I are working from home and raising our 6 month old daughter, and the -only- distraction that brings me to a grinding halt is my daughter's crying. Even with noise-cancelling headphones, if I hear any crying at all I feel an incredible emotional reaction that totally prevents me from focusing on work until she's calm and happy again. I'm also glad to read that there's a natural (hormonal?) explanation for the disproportionate effect that her crying has on me.