The two sides in Maryland’s same-sex marriage debate clashed Friday over a new television ad from opponents that warns that if Question 6 passes, “schools could teach that boys can marry boys.”

Marylanders for Marriage Equality, the group seeking to uphold the state’s gay nuptials law, called the ad a scare tactic, arguing that curriculum decisions are made by school boards and not subject to the Nov. 6 ballot measure.

The ad, which echoes some that have run in other states weighing the same issue, features a couple from Massachusetts, where same-sex marriages have been legal since 2000. The couples says that they were unable to opt out their second grader when he was asked in school to read “King & King,” a story about two princes who marry.

“Don’t make the same mistake and think that gay marriage won’t affect you,” parent Tonia Parker says at the close of the ad sponsored by the Maryland Marriage Alliance, the lead group seeking to defeat the law.