Sorry all, but I have to jump in here. ahem… very early spays and neuters are done routinely and as safely as on adult, maybe safer as they heal faster. There are as many MEDICAL reasons for doing it before the first heat as there are to wait. And if the hernia is a problem, you do risk losing your dog. With a normal small hernia, waiting til 6 to 9 mos wouldn't be a problem, but if your vet is concerned about the hernia, and it is abnormal as you describe, do what you and your vet think is best.
I work with rescues that spay/neuter as young as 10 wks. For large breed dogs, there is a link between neutering before 18 MONTHS and bone cancer. They have not studied smaller breeds yet. However with bitches, spaying before the first heat helps prevent mammary cancer.
Let me be clear, I am not really into spay/neuter ever if you can keep the dogs safely as far as breeding issues go and if you stay on top of routine checks for any lumps on bitches. But I think scare tactics should go out the window. Give the info, let the person make a good decision on their own based on facts. Cause Lisa, if your vet nicked the intestines, that is incompetency and having NOTHING to do with early spay/neuter. In fact, the research on early spay/neuter were done with puppies and kittens I think as young as 7 weeks old!
And for growth plates... the truth is early spay/neuter actually causes them to stay open longer and the bones to grow MORE. Sounds good if you want taller dogs... except, oh yeah.. that longer growth may be related to bone cancer. Again, I would wait til a dog was at least 2 myself, but it really is six of one half dozen of the other.