Gay parent Lance Anderson speaks out against the parental rights clause in Bill 44 on the steps of the Alberta legislature Monday. (CBC)

Gay rights activists made a final push Monday afternoon on the steps of the Alberta legislature to stop the passage of Bill 44.

The controversial legislation would give parents the right to pull their children from classes about sexuality, sexual orientation and religion. The final vote on the bill is scheduled for Monday night.

"I have to start by saying, 'Here we go again,' " gay rights activist Murray Billet said.

The parental rights clause is included in an amendment that finally enshrines gay rights in the province's human rights code, 11 years after the Supreme Court of Canada directed the government to do so.

"They have taken a very fundamental right and have added all kinds of what I would characterize as state-sanctioned discrimination, which is absolutely unacceptable," Billett said. "This is not about kids' rights or parents' rights. This is about discrimination."

Billet's statements were echoed by Lance Anderson, a gay man who is married and has two children in elementary school.

"I fought this government before to adopt my children. I won. I'll do it again," he said.

'This is not about kids' rights or parents' rights. This is about discrimination.'— Murray Billett, gay rights activist

Critics say the law would make it possible for parents to file human rights complaints against teachers and school districts, creating a chill with regard to what is taught in the classroom.

Anderson said the bill will affect what his children learn in school.

"If you have to take the curriculum and strip it or ignore every mention of every religion or sexuality contained in it, it really puts a damper on a lot of the basic education that my kids receive," he said.

"What happens at Father's Day art projects when my son makes two? How does the teacher explain that without talking about my family?"

The Alberta NDP were expected to table a petition against Bill 44 with more than 1,000 signatures on it in the Alberta legislature Monday afternoon.

Tory politicians say the bill does not discriminate against gay people and only gives parents a say in what their children are taught.

Lindsay Blackett, the cabinet minister responsible for human rights, said Monday he was frustrated by the amount of negative attention the bill has received.

"What's most misunderstood, I think, is that somehow that because we put in a parental rights bill that gave a parent the chance to opt out meant that that was somehow anti-gay and we didn't support the inclusion of sexual orientation and we had to come up with some side-door deal to make that happen, which is absolutely false," he said.

Opponents to the bill plan to fill the legislature gallery Monday evening while MLAs speak about Bill 44.

The governing Progressive Conservatives have 71 of the legislature's 83 seats, making it a near certainty that Bill 44 will pass a third and final reading in a vote expected to take place later in the evening.