I have been using the ergo baby carrier since 2012 with my oldest child. Yesterday while putting my 6 month old into it (back carry) he squirmed and threw his weight backwards while one leg was already restrained. Despite my best efforts to prevent him falling by holding on to the leg and also reaching behind me to support his weight he landed on the bed behind me and broke his thigh bone! Its has been a very stressful 24 hours including full skeletal xrays, multiple attempts at IV lines and being evaluated for possible abuse and neglect. He is now home and is wearing a hip dysplasia brace for the next few weeks. Just wanted to share my experience in case anyone else uses the ergo for back carry. I fully believe it takes two people to safely use it for back carry. DH has always complained about how hard it is to get on but I have never had an issue til yesterday.