For nearly 40 years, Sesame Street has helped kids learn about the world around them, and themselves. To that end, the series has routinely introduced Muppet characters that reflected the big, diverse world out there.

Aristotle

Sporadically throughout the 1980s, Sesame Street’s resident worrywart Telly hung out with a friend named Aristotle. He was blind, and in a few segments demonstrated to kids what life might be like for a blind person. One time, he helped human character David make baloney sandwiches (with David helping him find the necessary objects). On another episode, he reads “Little Red Riding Hood” to Big Bird out of a book printed in Braille.

Julia

In 2017, Julia became the latest Muppet to take residence on Sesame Street. She’s the first character on the show to be on the autism spectrum. (Muppeteer Stacy Gordon operates the puppet, and helped form Julia’s personality from observation of her son, who also has been diagnosed with autism.)

Alex

Millions of children have an incarcerated parent, and Sesame Street producers recognized that that must be a difficult situation. So, to help kids cope and process, they introduced Alex in 2013 in a special educational video called Little Children, Big Challenges: Incarceration. Alex at first doesn’t feel like playing with the other kids and Muppets because he’s so sad that his father is in jail, only to have an older kid tell him that he’s not alone, because she went through the same experience.

Abby Cadaby

This super-excited, magic-wand waving Muppet has been part of the regular cast of Sesame Street for more than a decade, but in 2012 she starred in a special Sesame Street video aimed at kids whose parents were going through a divorce. After Abby draws a picture of her house—or two houses, rather—she reveals that her parents are splitting up, and are living separately.

Kami

This Muppet was introduced on Takalani Sesame, the South African edition of Sesame Street, in 2002. The aim of Kami: to help kids learn about HIV and AIDS, and to lessen the stigma associated with it. Kami’s backstory: She received a blood transfusion as a baby, and it was unknowingly tainted with the virus.