I totally agree in letting a child in need cry for hours could be harmfull however in some instances like for sleep trainning I think it is necessary. We need to remind aoursefls and truly understand what and why we are leaving. Sleeping is AS imporant as eating or breathing. However this does not come as naturally because we all have very busy days naps and schedules do get interupted and it is easy for a young child to get into bad sleeping habits. I do beleive it is important for our child to know that we will be there for them and give them that security but I also beleive it is our job to teach them good and healthy habits and giving them self confidence. You are not just letting you child cry at night ..You are teaching him to sleep, you are showing him that he CAN do it by himself and that he IS secure. By doing that and ensuring he has a good sleeping habits, you are letting is immune system, brain development, body everything recharge ang give him better chance at everything. I beleive this is part of the parents job as well and at 11 month old, a child is totally ready to understand that and need 12 hours sleep at night plus naps during the day. You can do it anyway you want it but teaching your shild to slepp by himself is the best thing you can do for her.