This dog started and stayed a house pet a replacement for my sons Rottie I raised him like every other dog I ever owned FIRM but gentle , he was a wacko as a PUP he NEVER EVER went after any of the house hold members or people at our puppy school..if ANYTHING he was without a doubt the SMARTEST dog I ever owned examples every door had to be bolted he by 6 months had learned how handles worked..saw him drag a kitchen chair to re frig to get to a toy on top..(saw from my kitchen window) He also graduated #1 in his class at Puppy socializing and agility but despite all that HE NEVER liked people . And yes he was neutered at 5 months when I knew I never wanted to pass his genes on;My vet when he was 7 months old suggested U of Penn for blood work and complete exam by their doctors as he never saw anything as mean as this pup. I was told by U of P staff that there are 3 chemicals that regulate aggression ..he had all 3 I think testosterone level is one. they were amazed he was not dog aggressive.. they did say they never saw a neutered dog with his levels of testosterone Igmuska I respect your knowledge and posts , when I say blood tests that is what I was told or led to believe( I am not a Vet)..I know I helped them get blood vials from him at least 2 .They showed me a monitor with 3 spikes and explained to me he was chemically inbalanced..he would get so angry with them that he honest to god got the worst bloodshot eyes anyone ever saw..like his blood pressure was skyhigh..they gave him pills that were supposed to help him chill but after about a month and a half they were working about 40% of the time. I would venture a guess that he had no physical issue like cancer or liver disease because after spending about 2400.00 on him not 1 vet at 1 of the best vet Hospitals in the world had a clue what to do I can only tell you that he was NEVER abused from 6 weeks old to 16 months My son loved this dog and played with him 24/7 he slept in my sons room and was fed by my son and he played with my son but when I eliminated any source for him to attack he turned on my son..who did a bad thing and lied to me that he got torn up jumping a fence 11 stitches when the dog 1st got him at about 12 months 2nd time he got my son I was there and he laying down and w/o cause went after my son got him , I grabbed him knocked him on his ass and he backed down I put him outside and took my son to doctor (about 14 months) And I do not mean a quick snap bite I mean a full out shake head and rip attack which he only stopped because of my action..never a growl or a warning bark or anything..The last and final time we were in kitchen for breakfast my son was eating cereal when the dog came from behind me and just went berserk grabbing my son by the leg and my son was wailing on dog who just would not let go I hit him and tackled him at the same time and dragged him outside where I saw the bloodshot eyes he was about 16 months old.. Just some quick background my son(when he was born) came home from the hospital and was met by 3 big dogs..he came to work with me from 5 years old and up to feed and play with my work dogs ( never less than 5 at work), so its not like he not used to dogs or did not understand by 14 what to do with a dog. He never attacked me or my wife . But he got my vet his tech 2 Uof P vets a co worker 2 other pro trainers and my son..he went after 10-15 more people but thanks to good leash's and fences he did not get them. And since I have been saving dogs for over 25 years that my local shelters said were un adoptable and giving them a decent home and in all honesty with all those dogs a lot who were abused I never saw anything like this dog..and NONE of my dogs ever bit a kid stranger or not let alone the kid who was feeding them.