SAN FRANCISCO—California’s Roman Catholic bishops are urging parishioners to support a fall ballot measure that seeks to overturn the court ruling that legalized same-sex marriage in the state.

The California Catholic Conference issued a statement strongly encouraging parishioners “to provide both the financial support and the volunteer efforts needed for the passage of Proposition 8.”

In the statement, the bishops say their position is based partly on the presumption that while all people deserve to be treated with dignity, being raised by a married mother and father is “the ideal for the well being of children.”

The conference’s executive director said the bishops plan to develop materials that parish priests can use to address the topic between now and election day.

The conference represents the archdioceses of Los Angeles and San Francisco and the dioceses of Fresno, Monterey, Oakland, Orange, Sacramento, San Bernardino, San Diego, San Jose, Santa Rosa and Stockton.