US states with the highest proportion of Catholics are more likely to support gay rights, research has claimed.

According to a soon-to-be published study from scientists at Columbia University and research from Mark Silk from Trinity College, states which have the highest number of Catholics are more likely to support rights such as gay marriage, civil unions and protection from discrimination.

Jeffrey Lax and Justin Phillips of Columbia University examined public support and policy on eight issues including marriage, housing, adoption and sodomy laws.

Silk, who heads the Leonard Greenberg Center for the Study of Religion in Public Life at the college, combined their work with the 2008 American Religious Identification Survey.

He found: “Six of the eight states where 50 per cent or more of the public supports gay marriage are the states with the highest proportion of Catholics, ranging from Rhode Island at 46 per cent to New York and California at 37 per cent.

Despite pronouncements from Catholic bishops on the evils of homosexuality, USA Today writer Cathy Lynn Grossman has suggested that the link is down to a long history of Catholics campaigning for social justice.