TAMPA, FL - AUGUST 28: Delegates from Texas wear cowboy hats during the Republican National Convention at the Tampa Bay Times Forum on August 28, 2012 in Tampa, Florida. Today is the first full session of the RNC after the start was delayed due to Tropical Storm Isaac. (Photo by Win McNamee/Getty Images)

WASHINGTON -- Two Republican gay rights groups are calling out the Texas Republican Party for denying them the chance to put up booths at the upcoming state GOP convention in Fort Worth.

The Log Cabin Republicans and Metroplex Republicans held a joint press conference Thursday afternoon denouncing the party's decision.

"Overall, Log Cabin Republicans of Texas has found incredible support within the Republican party -- Texans, like the rest of the country, are evolving on LGBT rights issues," the group's chairman, Jeffrey Davis, said in a statement. "The Republican Party of Texas has even welcomed many of our members as delegates to the Texas State Republican Convention. However, the party has denied our several attempts to host a booth in the convention exhibit hall, citing archaic language in the party platform to support their actions."

State GOP chairman Steve Munisteri confirmed to The Huffington Post that groups advocating for gay rights are not allowed to put up booths at the convention, which runs from June 5 to 7. The issue, he explained, is that their position runs counter to the current party platform, which the state GOP adopted in 2012. A policy was established at the last convention, that groups wanting to set up booths can't advocate for positions that contradict the platform.

Indeed, the platform is quite explicit in its condemnation of same-sex marriage, stating that the definition of marriage is a "God-ordained, legal and moral commitment only between a natural man and a natural woman."

"We affirm that the practice of homosexuality tears at the fabric of society and contributes to the breakdown of the family unit," it adds. "Homosexuality must not be presented as an acceptable 'alternative' lifestyle, in public policy, nor should 'family' be redefined to include homosexual 'couples.'"

Munisteri said gay rights groups are not being singled out; groups that promote gambling and marijuana legalization have also been turned away for the same reason.

"They asked to meet with me, I met with them," said Munisteri of the gay rights groups. "I returned all their phone calls, we responded to all their emails and explained, if you don't like the policy, you have the right to go to the convention as a delegate and try to get the policy changed."

"The policies are adopted by members of the state Republican Executive Committee, who are on the officials committee, and they certainly can run for those offices or support candidates who will change the policy," he added. "Or if, for any reason, the platform were changed and they were advocating something consistent with the platform, they could do it."

Gregory T. Angelo, executive director of the national Log Cabin Republicans, suggested in a statement that the Texas GOP's exclusionary policy would hurt it at the ballot box.

"This isn't about disagreements we may have on civil marriage; this isn't about the party platform -- this is about an anti-gay wing of the party that hates gay people so much they can't even stand to see us acknowledged as a necessary part of a winning Republican coalition," he said. "At a time when Democrats are working overtime to turn Texas from red to purple and then a vibrant blue, now is not the time for the politics of subtraction and division in the GOP; it is time for addition and multiplication. The Texas State GOP and its leadership ignore that advice at their peril."