The Gay and Lesbian Equality Network (GLEN) is criticising a Broadcasting Authority of Ireland (BAI) ruling on a same-sex marriage discussion.
The BAI upheld a complaint from the Family and Media Association - a group which promotes Christian values - that the item was unbalanced.
The discussion took place on the 'Derek Mooney Show' on RTÉ Radio 1 last January.
It contained an item discussing the latest civil partnership figures with broadcaster Michael Murphy and Tiernan Brady from GLEN.
GLEN chairman Kieran Rose said "The ruling has implications for all issues that are topics under public discussion, not just lesbian and gay issues."
"Does it now mean contributors to a broadcast programme may not now talk about possible future constitutional change on any issue, unless the programme segment has opposing views?".
"We would have serious concerns that this ruling would restrict open debate on issues that directly impact lesbian and gay people in Ireland," he added.
Brian Sheehan is the director of GLEN. He says it should be possible to discuss gay and lesbian issues without somebody having to oppose them.