Texas Governor Rick Perry, Minnesota Rep. Michele Bachmann and former Pennsylvania Senator Rick Santorum are among the 5 presidential candidates who oppose gay marriage, repeal of “Don't Ask, Don't Tell” (the policy set to expire on September 20 that bans gay and bisexual troops from serving openly) and laws that would prohibit workplace discrimination based on sexual orientation and gender identity.

According to Marriage Equality USA, former House Speaker Newt Gingrich and Michigan Rep. Thaddeus McCotter also uniformly oppose gay rights.

At Thursday's GOP debate, Santorum chided Texas Rep. Ron Paul, Bachmann and Perry for their weak opposition to gay marriage.

“This is the 10th Amendment run amok,” Santorum said. “We have Ron Paul saying, 'What the states want to do. Whatever the states want to do under the 10th Amendment is fine.' So, if the states want to pass polygamy, that's fine. If the states want to impose sterilization, that's fine. No, our country is based on moral laws, ladies and gentlemen.”

“You have to fight in each state, and that is where I disagree with Rick Perry; I disagree with Michele Bachmann,” he later stated.

Yet Perry, who jumped into the GOP race on Saturday, and Bachmann also oppose gay marriage and support a constitutional amendment defining marriage as a heterosexual union.

Of the 13 presidential candidates listed on the group's chart, only Fred Karger, who is openly gay, received a perfect score. President Barack Obama's positions on marriage and workplace protections in the private sector are listed as “maybe.” Former Massachusetts Governor Mitt Romney might support gay couples' right to adopt children and repeal of “Don't Ask, Don't Tell.”

(Related: Michele Bachmann's gay comments praised by GOProud's Chris Barron.)