Gay marriage supporters see 41 reasons to fret over the Supreme Court’s decision to take up the case of California’s ban on same-sex unions.

While nine states allow same-sex partners to marry, or will soon, 41 states do not. Of those, 30 have written gay marriage bans into their state constitutions.

That fact is worrisome to those who firmly believe there is a constitutional right to marry, regardless of sexual orientation, but who also know that the Supreme Court does not often get too far ahead of the country on hot-button social issues.

“Mindful of history, I can’t help but be concerned,” said Mary Bonauto, director of the Civil Rights Project at Gay and Lesbian Advocates and Defenders and a leader in the state-by-state push for marriage equality.