UC Davis is doing further research into the timing of the spay/neuter and trying to determine what is best.
https://www.indiegogo.com/projects/when-should-you-spay-or-neuter-your-puppy
Some people are promoting vasectomies for dogs and removal of the uterus only in females. In Havanese this is not particularly difficult but in larger more imposing breeds it may be a problem. I have been told that most dogs in Europe are left intact and it does not seem to present a problem. I suppose it all depends on what people are use to and the culture around this issue.
