a reputable breeder would be making sure that the puppies are spayed/neutered regardless. They can be the picture of health. If the breeder isn't keeping them him/herself for breeding purposes, they must be speutered. No compromise on that one.
or a non-breeding contract is also acceptable... most reputable breeders will only sell to people they trust and contracts are not written up for nothing. granted, it's a trust issue, but nonetheless you cannot "force" a buyer to sterilize their pet, i mean who has time for policing? and withholding papers until proof of spay/neuter only works for some buyers, some don't care one way or the other... it's a sticky situation, all right. We own a papered, purebred dog under a non-breeding contract and he's not neutered, we might get it done down the road but for now, we like him this way and the breeder is fine with it. our female is spayed so the household remains quiet. so... every situation is different, IMO.