Opposite thought, I personally think a vet that recommends s/n at 8 weeks of age isn't a good vet. They are not taking into consideration the dog's growth. Reproductive organs are used for more than making puppies, they secrete hormones that the dog needs to grow properly. Larger breed dogs can have issues with s/n too early- they don't fill out properly and are often too tall for the breed standard. We have 2 fixed dogs, and one intact. We won't alter him till he's completely grown, which may be 3 years old. He's 20 months now. He doesn't hump, doesn't roam, and has no bad habits resulting from being intact. It has nothing to do with manliness or ego, it's our preference to keep him intact for now, and we're responsible with him so the risk of him getting a dog pregnant is very low.