The CW has topped GLAAD’s list of networks doing the best at representing diverse images of lesbian, gay, bisexual and transgender people on TV.

The Gay and Lesbian Alliance Against Defamation evaluated the quantity, quality, and diversity of LGBT people on primetime programming of five broadcast and 10 major cable networks in its sixth annual Network Responsibility Index.

GLAAD gave CW, ABC, and Fox the highest marks for being LGBT inclusive. CBS, History Channel, and TBS all received failing marks.

CW targets young audiences with its programming and features LGBT characters on shows such as ‘Gossip Girl’ and ‘90210.’

LGBT characters like Eric (Connor Paolo) on ‘Gossip Girl’ and Teddy (Trevor Donovan) on ‘90210’ are regular cast member and not the focus of a single “very special episode.”

The practice, common in the ’80s and early ’90s, of having an LGBT character appear on one episode and then disappear from the show is less acceptable now.

“Americans expect to see their off-screen worlds represented onscreen and today more than ever that includes LGBT people and families,” GLAAD president Herndon Graddick said.

Networks like the CW and ABC, which primarily target younger audiences, received high marks from GLAAD. Recent studies of have found that young people are far more accepting of LGBT rights and lifestyle than older generations.

This could explain why CBS fared so poorly in the GLAAD index. CBS focuses on attracting older viewers. The network’s score dropped two percentage points, moving from an “adequate” rating to a failing score.

CBS has finished in last place on the GLAAD Network Responsibility Index for four years running.

Read the full 2012 GLAAD Network Responsibility Index.