The head of PBS won't rule out the appearance of an HIV-positive Muppet on Sesame Street, saying the show's approach will reflect the virus' impact on U.S. children.

An HIV-positive character will join South Africa's version of the show in September, and some federal lawmakers had grown alarmed by the possibility of such a character joining the U.S. show, questioning whether it was age appropriate.

PBS President Pat Mitchell told the Television Critics Association on Friday that the South African character grew from the needs of that country, where millions of children are affected by AIDS.

If the virus became a more serious problem for U.S. children, Sesame Street would be as responsive as it has been to other topics, Mitchell said.

The public television show aimed at preschoolers has dealt with the issue of death before, Mitchell noted.

She and the show's producers had previously said no HIV-positive character was planned in the U.S. version.

South Africa's Takalani Sesame is one of several locally produced versions of the children's program, which premiered in the United States in 1969.

Its new HIV-positive Muppet character was created at the urging of the South African government to educate children about AIDS.

Some 4.7 million South Africans — one in nine — are HIV positive, more people than in any other country.