MADISON, Wis. -- A plan to allow students to remain enrolled in online charter schools is in doubt after the governor said he wanted last-minute changes.

The development leaves the future of schools where students learn over the Internet from home in question.

Those schools are facing closure after a state appeals court in December ruled the largest such school was operating in violation of state law.

Lawmakers responded by crafting a bipartisan agreement that would allow the schools to remain open.

Gov. Jim Doyle told lawmakers that he wanted a study of how students are being served in those schools and a cap on enrollment at the existing level in the meantime.

The Democratic-controlled Senate voted 17-16 to accept those changes.

Wisconsin virtual school families rallied at the state Capitol Tuesday to oppose an amendment that could stop new students from enrolling in virtual schools. The group said that special needs students could be affected by the change.

Their parents and teachers said that without an at-home option, Wisconsin schools would need increased aides in the classroom to help children on an individual level.

"My special needs kids have a variety of disabilities. Sometimes their needs are too numerous to be met in the traditional classroom. Virtual schools are a great option for these kids," said Kaye Martin, a Wisconsin virtual schools teacher.

The bill and its amendments face uncertainty in the Assembly.