On Tuesday, South Dakota passed a controversial bill about transgender bathrooms that has been described as discriminatory by activist groups.

And one lawmaker is speaking out.

Last week, South Dakota House Rep. Bernie Hunhoff (D-Yankton) drew a stark comparison between the segregated drinking fountains of the 1950s and legislation requiring that transgender students use bathrooms and locker rooms according to their biological sex.

Many of the responses to Hunoff were negative, but the lawmaker defended his position in the comments:

Facebook - facebook.com

And at least one man identifying as transgender tried to reason with supporters of the bathroom bill:

Facebook - facebook.com

The passage of the so-called "bathroom bill" makes South Dakota the first state in the nation to come this close to implementing such a rule, the Washington Post reports. The legislation now goes to the state's Republican Gov. Dennis Daugaard, who previously voiced approval for the bill.

The bill would require students to use bathrooms according to their biological sex. Transgender students would have separate bathrooms, the Post notes.

Hunhoff wrote in a Facebook post that he hoped future generations would not study discrimination through the example of separate bathrooms.

"My hope is that in 50 years my great-grandchildren don't 'google' discrimination and find a photograph taken of separate bathrooms here in South Dakota, the state we love," Hunhoff's Facebook post reads.

Flickr/Cory Doctorow - flic.kr

The bill has drummed up outrage from LGBT rights groups, as well as prominent civil liberties organizations such as the American Civil Liberties Union, which issued a petition calling on Daugaard to veto the "awful measure." If passed, the measure could "set a horrifying standard for the rest of the country to legislate hate," the ACLU said.

While opponents say it infringes on students' rights under federal Title IX protections, which cover sex discrimination, proponents contend that the bill actually upholds the same provisions that require separate facilities based on gender. In 2014, the Department of Education clarified that Title IX protections should protect sexual identity — not just biology.

Transgender students have struggled with facility use before. Last week, a "bathroom bill" in Virginia was voted down.