To be honest, this show is a breath of fresh air in the land of TV crime drams. The plots are refreshing rather than repetetive, and don't depend on the headlines to make a story. The characters however, are what makes it. They're interesting and play off each other wonderfully, and kids are sure to pick out people in their own lives who "fit the mold" of leader or partner. It's not so much stereotyping as it is providing characters whose role is grounded more in a fictional world than trying to be "real".
Some parents may be concerned about the sexual content and launguage used in the show, but often times, kids will hear much worse from their friends at school, so it's an oppurtunity to talk to them about why that kind of language or behavior isn't appropriate for them.
The show regularly deals with recurring themes of family, loyalty, trust, and teamwork, and each of the characters have good values and morals and believe in their work. There are also "the rules" which is something like an informal moral code the agents follow.
NCIS is also a very diverse show. The agency is portrayed as having a African-American director, one of the main characters is devoutly jewish, and another is Italian. The criminals come from different backgrounds and the reasons for their actions rarely fall back to race. Despite the sometimes sexsist attutudes on the show, it goes to lenghts to show that women can be smart, strong, powerful, and respectable people without being sex objects. In the current season, there has been a subplot dealing with one of the characters becoming a US citizen and what the process entails, both officially and emotionally.
The respectful and honorable way that NCIS deals with the military and counterterrorism, especially in these times, is also commendable.
Becasue of the show's "crime" theme and sometimes inaaproprate content, I'd reccomend this show for children ten years and over, though some episodes are okay for younger children, at parents' discretion.