After heated debate before the board of education, three families from different religious backgrounds sued the school system.
They alleged the policy violated not only state law, but their free speech and substantive due process rights, under the First and Fourteenth Amendments.
On Thursday U.S. District Judge Deborah L. Boardman disagreed, declining the parents' request for an injunction.
"The court concludes the plaintiffs' asserted due process right to direct their children's upbringing by opting out of a public-school curriculum that conflicts with their religious views is not a fundamental right," Boardman wrote in a 60-page opinion.
CAIR responded to the ruling by issuing this statement.
"As the school year begins, we remain committed to vocally advocating for families who simply want their children to attend English class without being forced to discuss and affirm sensitive concepts that would normally arise in sex education courses. Until the opt-out is restored, families plan to pursue every available legal means to protect their rights — including but not limited to targeted legal action, continued interfaith protests, and the release of additional internal MCPS documents."
Attorneys representing the parents have already filed a notice of appeal.