Opponents need to collect more than 500,000 signatures by Wednesday to get the issue on the ballot.
It's very difficult to qualify a referendum with no money, but those who don't want gay history taught in California schools were in the midst of an 11th-hour push Tuesday.
Time is running out for conservative groups that have been trying to gather signatures for a referendum to overturn a new law requiring that historical contributions of gays and lesbians be included in school curriculum.
StopSB48.com has a countdown clock on its website that says they have less than 24 hours to turn in more than 505,000 valid signatures.
"It's very difficult without paid signature gatherers, but the groundswell is so great, that it is actually possible that we just might make it," said Brad Dacus, Pacific Justice Institute.
But a last-minute email plea to supporters says it would take a "miracle" to get the number of signatures required to qualify the referendum, and that help is needed.
Gay rights groups are crossing their fingers, hoping the effort falls short.
They've been working for years to get themselves included in textbooks.
"It's necessary because there's a whole community that has been censored out of our education system," said Mario Guerrero, Equality California.
What has hurt the referendum movement is the lack of big money that was behind Proposition 8, the controversial initiative that banned same-sex marriage in California.
The repeal on Senate Bill 48 has mostly been a volunteer effort centered around concerns that schools will teach homosexuality.
If it fails to meet the Wednesday deadline, the same groups may try for an initiative on the November 2012 ballot.
"When it comes to defending the rights of parents and protecting children, we at Pacific Justice Institute are willing to look into all avenues necessary to be able to do so," said Dacus.
Supporters of the inclusion of gay history say the new textbooks could help combat bullying and promote greater understanding. They don't want to wait and feel the new books are needed now.
"It would mean so much. If it had been around when I was younger, it probably would have saved me from a lot of the trauma I had to go through," said Javier Pinedo, a bullied teen.
Since California is the largest textbook buyer in the country, publishers will typically try to sell the California edition to other states. So this fight could have national implications.