A new book on the television industry, Primetime Propaganda: The True Hollywood Story of How the Left Took Over Your TV, says Sesame Street is just one of many shows that uses its storylines to forward liberal causes.

"We definitely have a social agenda," explained Shari Rosenfeld, a vice-president with the organization that produces Sesame Street for markets around the world.

Author Benjamin Shapiro based his book on interviews with some of the biggest producers and directors in the television industry. In frank and tape-recorded conversations with the people who brought you shows such as MASH, Friends and House, Hollywood insiders admit using their shows not just to entertain, but to force cultural change.

"I mean you have a bunch of liberals running the show," Marta Kauffman, co-creator of Friends, told Shapiro during an interview in her office on the Warner Brothers' lot.

Kauffman also admits using the relationship of Ross' ex-wife Carol with her lesbian lover Susan as a way to push acceptance of same-sex relationships. During the episode in which Carol and Susan get married, the minister was played by Candice Gingrich, sister of Republican stalwart Newt Gingrich, something Kauffman admits was a "f--- you" aimed at the right wing of American politics.

Throughout the book Shapiro admits his love of television and admiration for several shows of which he is critical.

What Shapiro, a nationally syndicated political columnist, would like to see is more balance rather than the complete dominance of left-wing politics.

"Based on the testimony of hundreds of writers, producers, actors and television executives," Shapiro writes, "it has become abundantly clear that television has evolved from a medium for entertainment and advertising into a funnel for socially liberal messages."

Unlike other critics of television and its impact on popular culture, Shapiro calls on conservatives to get involved and fix the problem rather than just turn off the TV.

"Nobody wants to turn off the television because television is great! Television is just too much fun for people to turn it off," Shapiro writes.

Shapiro will appear Tuesday night on a special one-hour episode of Byline on Sun News Network.