A Kansas University researcher says that gay marriage bans may have generated empathy for same-sex couples and their families.

Political science professor Don Haider-Markel has researched gay and lesbian political movements in the United States. He also wrote “Out and Running: Gay and Lesbian Candidates, Elections and Policy Representation.”

Haider-Markel says that without states pushing to ban same-sex marriage in the 1990s, people might not have been exposed to stories about the difficulties gay couples experience without marriage. Haider-Markel called that opinion-changing coverage “an ironic outcome.”

Today, six states and the District of Columbia have made same-sex marriage legal, and 12 more recognize civil unions or have domestic partner laws. Recently, three more state legislatures voted to permit gay marriage, although the New Jersey legislation was vetoed.