Several weeks ago, "Sesame Street" quietly introduced a new character: Alex, a blue-haired, green-nosed Muppet who has a father in jail. In one scene, Alex sits on his front steps and doesn't want to play, upset that his father is away. But Alex soon receives the comfort of an older friend, who says she has gone through the same thing.

Alex looks like the other Muppets, and was shot on the standard "Sesame Street" set. But he won't appear on PBS anytime soon, according to the show.

Instead, "Sesame Street" episodes featuring Alex will be available in state and federal prisons in 10 states across the U.S. in the coming months, including Riker's Island in New York, which the "Sesame Street" cast and crew visited on Father's Day, and – more importantly – in the homes of family members of the inmates.

Incarceration is just the latest thorny topic the beloved children's television series is tackling. Over its 40 years, Muppets on "Sesame Street" have addressed AIDS, divorce, a parent's deployment overseas and a death in the family.

But the show is addressing incarceration in a way it didn't used to: by bringing the show directly to the kids and families it wants to reach.

"Sesame Street" was built on the idea that a show that could capture a child's attention could also give the child an education. That idea turned out to be wildly successful. On the show's 10th anniversary, in 1979, some 9 million children in the U.S. were watching the show. By 2006, it was the most-watched children's show in the world.

With that popularity, "Sesame Street" took the opportunity to tackle some of the most difficult issues children faced. In 1983, an episode aired in which Big Bird learned that the owner of Hooper's Store, Mr. Hooper, had died, and refused to believe he wouldn't come back. "Who's going to take care of the store? And who's going to make my birdseed milkshakes?" Big Bird says. His older friends reassure him they will help.

And in 1992, the show attempted to address divorce, creating an episode in which the parents of character Mr. Snuffleupagus ended their marriage. But after testing it, "Sesame Street" decided the topic was too confusing to kids, and the episode was scrapped. Several years ago, the show tried again, but Lynn Chwatsky, vice president of outreach initiatives and partners for Sesame Workshop, the show's nonprofit, says it still didn't work. "Most of these kids' reactions was: 'Oh my god, my mommy and daddy are going to get divorced.'"

So "Sesame Street" recently tried something new: They made the episode, and then targeted it specifically to kids with parents with divorce.

The reaction this time was very different. "It was: 'My friends on "Sesame Street" are going through the same thing,'" says Chwatsky. "We actually do learn from our mistakes around here."

Now, "Sesame Street" is applying that lesson to the subject of incarceration, seeking to reach kids and inmates directly by working with state Departments of Corrections, criminal justice groups, and social workers, after-school programs or others in the local community. According to Pew Charitable Trusts, 1 in 28 children in the U.S. – or about 2.7 million kids – have a parent in jail. "Sesame Street" says it plans to hand out half a million resource kits with DVDs featuring the character Alex, as well as advice and encouragement for kids and families dealing with an incarcerated family member.

Elizabeth Gaynes, executive director of the Osborne Association, one of the largest multi-service criminal justice organizations in the country, regularly works with children with incarcerated parents in the New York area and partnered with "Sesame Street" for the initiative.

"This is an issue we've been struggling with for years. Kids are ashamed of it, or scared people will think they are like their parents," she says. "But Alex made it more accessible for kids to talk about."

The effort has so far been hailed by educators and health advocates. The Educator's Room, an education website, applauded "Sesame Street" for tackling the "taboo topic" of parents in prison. Kellee Terrell, who runs the health web site TheBody.com, commended "Sesame Street" in BET for "breaking the silence and encouraging a conversation" on incarceration.

But some think the taboo topic should be addressed more widely, including Gaynes at the Osborne Association.

"I would like to see Alex on PBS," she says. "It should be available not just for parents who have a kid in jail, but for kids who know somebody who does – because the stigma comes from other people."

Though Alex likely won't appear on PBS, "Sesame Street" has made some efforts to reach a wider audience on incarceration. On Tuesday, the show began tweeting from the perspective of a child with an incarcerated parent, writing: "Children with an incarcerated parent feel a complex array of emotions," and sharing a Vine video that read, in child's handwriting: "Sometimes I feel ashamed and confused. Other times I feel happy because I get to see my mom."

Chwatsky says the decision to keep Alex and incarceration online and off TV wasn't made lightly.

"Every single topic is looked at individually. Certain topics are good for all audiences, certain topics are not," she says. "Alex is intended to reach kids who have been impacted... by parents with incarceration."