A liberal-leaning church said CBS and NBC rejected a national spot because it alludes to condemnation of gay relationships by some churches.
The 30-second spot launched Wednesday highlights the Cleveland-based United Church of Christ's welcoming stance toward gays and anyone else who might feel shunned elsewhere.
The networks said the spot was too controversial to broadcast because it implied exclusion of gay and lesbian couples by other groups, according to the UCC.
A CBS spokesman said gay relationships were a matter of public debate and "we have a long policy of not accepting advocacy advertising."
NBC spokesman Alan Wurtzel said the network rejected one of two ads it received from the UCC because it violated the company's policy of not accepting ads that deal with "issues of public controversy."
The ad was accepted by ABC Family, AMC, BET, Discovery and TBS, among others, the church said.
The ad, part of a 3½-week, $1.7 million campaign, shows a muscular bouncer working a rope line outside a nameless church and deciding who is eligible to enter and worship.
"No, step aside, please," he says to two men holding hands.
Across the screen comes the message, "Jesus didn't turn people away. Neither do we." The final scene shows two women embracing.
"We're doing it because we made a discovery: There are lots of people out there who don't know we exist," said Ron Buford, who is coordinating the program for the 1.3 million-member denomination, down from 1.7 million in 1989.
The UCC has 6,000 congregations.