The First Amendment is being invoked by a group of concerned parents in Southern California who  argue that teaching children yoga in public school constitutes the introduction of religious beliefs into the classroom, according to ABC News.

Sixty parents in all have retained First Amendment lawyer Dean Broyles to challenge ashtanga yoga classes in the K-6 elementary schools of the Encinitas Union School District in San Diego County. They have not filed a lawsuit but are threatening to do so.

The biweekly, 30-minute classes come from a $533,000 grant from the Jois Foundation to the EUSD. The Jois Foundation is a non-profit which seeks to spread ashtanga yoga throughout the world. Broyles says billionaire hedge-funder Paul Tudor Jones and his wife Sonia Jones, a disciple of Sri Pattabhi Jois, the recently deceased master of ashtanga yoga, are targeting the district.

Under the grant, the district’s implementation of ashtanga will be studied by the University of Virginia and the University of San Diego, where researchers hope to learn about yoga’s effect on childhood education.

Despite the heat from the parents and their lawyer, district Superintendent Tim Baird stands behind the grant and the program.

"Yoga is a physical activity that's completely mainstream," Baird told ABC News. "It's done in universities and churches around the world. I understand it has a cultural heritage coming from India, and there are people that use yoga in their religious practices. … We are creating lesson plans in kid-friendly language that is really redesigning the program. We are not using cultural references. We are not using Sanskrit. We've changed the names to gorilla pose, and mountain pose."

Broyles, and the parents he stands with, strongly disagree, however. They’re saying all poses and commands in ashtanga have religious significance.

"On the wall there was a poster that showed the ashtanga. There are words showing what the limbs are,” said Broyles. "The ultimate goal is to be absorbed into the universe, which is called samadhi. They had a poster depicting that. Fundamentally it is a Hindu religion being taught through ashtanga yoga."

Apart from the religious issue, some EUSD parents feel yoga is a poor allocation of physical education time. Instead, they’d like to see their children doing more rigorous activities. They also claim that non-yoga PE time has been wasted, and that their children have been given no alternatives when they opt out of the ashtanga classes.

Overall, Broyles sees a great modern hypocrisy in the introduction of yoga. If it were Christian beliefs being taught, he asks, would parents be okay with it?

"If we were introducing Christian worship of bowing, there would be outcry in the community," he said. "Allowing our public schools to actively promote the beliefs and practices of one religion over others to young impressionable children sets a dangerous precedent."