I have researched this subject for years. I have shared my opinions with a lot of people, but hesitated to place a page on my website making recommendations. I have always recommened that pet owners should wait until the puppy had gone through their hormones. At least around 1 year old. After much thought and consideration, I think all people should have information relating to this subject before making their decision. I am therefore happy to give you information you can take to your vet and discuss with him/her.
You may not agree with these theories because of your vet's recommendations. But bear in mind that vets are taught to spay and neuter around 6 months. Many of them, hoiwever, as Dr. Becker, that this may not be the best option. I think of it in relation to what would happen if we had done this to our young children. The repercussions would have been horrendous.
Here is a research paper that Dogtor J feels is worth of being published on his website: