DENVER -- The archbishop of Denver on Tuesday defended a decision by a Catholic school not to allow two children to continue as students because their parents are a lesbian couple.

Archbishop Charles J. Chaput said it was a "painful situation," but the decision by Sacred Heart of Jesus parish school in Boulder was in line with church teachings.

Chaput said the school told the parents that one of the children could complete kindergarten and the other could complete preschool, but neither could continue after that.

Previous reports indicated only one child was involved. Neither the parents nor the children have been identified.

Mindy Barton, legal director of the GLBT Community Center in Denver, which supports gay, lesbian, bisexual and transgender people, said she believes the school was within its legal rights.

Barton has said the center would still investigate to determine whether the school violated any discrimination laws.

About two dozen protesters stood outside Sacred Heart of Jesus church on Sunday with signs, one reading "God loves all people."

"God and Jesus would not allow discrimination in that way," Joellen Raderstorf told 7NEWS at Sunday's protest.

"I just feel the Catholic Church is a church that should be teaching acceptance and tolerance. I just don't think this is an example of that," Juli Aderman-Hagerty told 7NEWS as she was leaving Mass on Sunday. "Father Breslin said it right. We're all sinners. Why discriminate against this end of sinners?"

However, not everyone disagreed with the parish's decision.

"People who understand the Catholic teaching will understand why the decision was made," said Fabien Ardila, a member of the parish.

In his written statement Tuesday, Chaput said the parents of Catholic school students are expected to agree with church beliefs, including those forbidding sex between anyone other than married, heterosexual couples.

"The church cannot change these teachings because, in the faith of Catholics, they are the teachings of Jesus Christ," he said.

Chaput said Catholic schools work as religious partners with parents, but that doesn't work if the parents don't respect church beliefs or openly reject them. He said that also puts unfair stress on the children and their teachers.

Chaput acknowledged that many Catholic schools accept students from other faiths and from single-parent families, but he said their parents are expected to support the Catholic mission of the school.

He said the church doesn't believe God has any less love for the children of gays and lesbians than for other children, or that gays and lesbians are bad people.