According to the survey, 84 percent of Reform rabbis perform intermarriages, while 16 percent do not. Among Reconstructionist rabbis, 88 percent officiate at intermarriages and 12 percent do not. Eight Conservative rabbis of the 59 surveyed said they officiate at intermarriages despite a prohibition by their movement.

Orthodox rabbis also are banned from officiating at intermarriages. The Reform and Reconstructionist movements allow their rabbis to officiate at intermarriages.

The findings represent a jump over the past two decades in the percentage of rabbis who would perform intermarriages. In 1995, a survey of Reform and Reconstructionist rabbis found that a combined 47 percent would officiate at intermarriages.

The study was conducted in 2017 between August and October and commissioned by Interfaith Family, a group that supports intermarried couples in Jewish life. It surveyed nearly a quarter of America’s 2,200 Reform rabbis and nearly half of the country’s more than 300 Reconstructionist rabbis, as well as nearly 60 Conservative rabbis and some from smaller denominations.

In the latest survey, most Reform and Reconstructionist rabbis (59 percent) require couples they marry to commit to keeping a Jewish home and/or raising Jewish children, according to the survey. Forty-three percent of rabbis from the two denominations require that the children not be “promised” to another faith, and 22 percent require that the non-Jewish partner not be committed to another religion.

About a quarter of the Reform and Reconstructionist rabbis require the couple to study Judaism ahead of the wedding, and nearly a third said they counsel interfaith couples differently than couples in which both people are Jewish.

But most Reform and Reconstructionist rabbis will not co-officiate a wedding with clergy of another religion. Only 26 and 22 percent of Reform and Reconstructionist rabbis, respectively, will do so, and only 20 percent of the rabbis will conduct a ceremony with theological references to another religion. About half of the Reform and Reconstructionist rabbis who do not co-officiate did say they would allow non-Jewish clergy to perform readings or prayers at the wedding.

Reform rabbis who were ordained in recent years were more willing to officiate at intermarriages than rabbis ordained in previous decades, but were less willing to co-officiate with non-Jewish clergy. Approximately 90 percent of Reform rabbis ordained after 2000 said they perform intermarriages, as opposed to 80 percent of those ordained before 2000. But 27 percent of rabbis ordained before 2000 said they would co-officiate, compared to 23 percent of those ordained after 2000.