i neutered hugo at 7 mo. if i had to do it all over again i would probably wait til he was at least a year. several good reasons for neutering at 7 mo. was his "equipment" is very small and you can rub his tummy without things getting in the way, he has never lifted his leg once-he still squats, didnt go thru "puberty" and have raging hormones. but him being neutered young, i feel like he missed out on some important hormones that effected his bones and growth as well as physical appearance (he has more of feminine look as opposed to some of his relatives who were not neutered as young such as thinner neck and head, less masculine muscle tone, etc. i could be totally wrong about this, it may not have a thing to do with his growth and appreance, but next giant i get will be neutered later on, after a year or so old. as far as humping goes, hugo never humped as a puppy, but will get excited if he is around a female who is in heat or just had puppies-go figure....