The Gay and Lesbian Alliance Against Defamation (GLAAD) posted the results of its sixth annual Network Responsibility Index and CBS, History Channel and TBS all drew low marks.
Those networks did not do well in the study, which maps the quantity, quality and diversity of images of lesbian, gay, bisexual and transgender individuals on TV.
In the study, GLAAD evaluated programming on five broadcast and 10 major cable networks, finding that the number of LGBT images stabilized this year as overall impressions continued to grow, according to the Hollywood Reporter.
And while those three networks failed, others did well. CW lead the way with 29 percent of its primetime programming hours being LGBT inclusive. CW also had the most racial diversity with 62 percent of impressions made by LGBT people representing characters of color.
ABC and Fox took the silver and bronze (up 4 percent and down 5 percent, respectively) with NBC finishing in fourth, despite a 4 percent improvement over last year.
CBS slid back 2 percentage points from 2011 and slid from an "adequate" score to failing marks, finishing in last place for the fourth year in a row.
On cable, 46 percent of Showtime's primetime fare was found to be LGBT inclusive, followed by ABC Family (34 percent), TNT (34 percent) and HBO (33 percent).
TBS drew low marks for the fourth year in a row. Only 5 percent of its primetime offering found to be LGBT inclusive.
History drew 3 percent.
"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. "Story lines of families like Mitchell and Cameron on Modern Family and young people like Emily on Pretty Little Liars are not only growing acceptance of our community, but have found praise from viewers and critics alike at a time when visibility and acceptance of LGBT people is at an all-time high."
The full cable rankings follow:
ABC Family 34%