Hi Debbie!
About 10 years ago, when I was still in HS my parents let me have 2 ferrets. First, I want to say that I absolutely adored them and they were great pets. I would say they are between a cat and a dog, personality wise. Secondly, they DO have an odor, but I would give them baths with Johnson & Johnson shampoo once per week and it helped tremendously. You can litterbox train them but they sometimes would stray outside of the box. If you have wall-to-wall carpet, you might not want them since they tend to try to get under things, so they will scratch at the carpet until there is nothing left in the spot. Also, you would need to ferret proof your house. Their natural curiosity can make quite a mess, especially if you have plants.
All that said, honestly, I don't think they are the right kind of pets for most teenagers. They require a lot of care, plus tons of attention. You can't leave them in a cage all day, but you can't leave them loose and unsupervised. Now, I would probably make a much better ferret owner now because I am much more responsible but I really don't need the hassle. BUT, if you feel your son is more responsible than most kids, than he might do great at it. Only you know him to judge that. I ended up giving them away because after HS graduation I didn't have the time to spend with them and my parents were not too fond of them. They were not fond of them, ONLY, because I began to slack in my care for them and things got messy.
If you do decide to get one for him, you will see that they are lovely animals who are extremely friendly and curious. They are tons of work, but also tons of fun.
PS-mine NEVER bit me or anyone for that matter.
Edited to add: Hey, I grew up in Morristown, NJ!! What a small world.
Sarah:7