I just hate watching movies that show turtles being kept like cats and dogs. It just irritates me knowing that their place is in their habitat. There's nothing wrong with taking them outside for direct sunlight in a kiddie pool or something else suitable, but even then you'll want to supervise them. It is stressing on them to be picked up in general or be moved from their "comfort zone"/habitat.
Some turtles are more aggressive than others on the biting thing. Until you learn your turtles personality, be careful when little ones are around. Even if he tries to bite, remember this is usually not a sign of meanness but natural instinct to protect themselves.
Most will agree that they are perfectly content in their habitat and do not need to "roam". Just be sure to clean/disinfect any surface that your turtle, his water or equipment comes in contact with. If proper hygiene is followed then health wise there's nothing to be concerned with for you and your family.