Officials in Texas are set to vote Tuesday on a new public school curriculum that incorporates lessons from the Bible as early as kindergarten, that provoked criticism from advocacy groups and families across the state.

Texas education officials voted narrowly to offer preliminary approval on Tuesday for a new curriculum that includes Bible lessons for children starting in kindergarten, part of a growing effort in the state and elsewhere to bring Christian principles to public schools.

Critics say the curriculum, which would be optional, unfairly promotes Christian beliefs in public schools in Texas.

School districts serving more than two million elementary-school children would be able to adopt a curriculum that draws on the Bible.