As the U.S. Supreme Court takes up the issue of same-sex marriage this month, thousands of LGBT couples are gearing up for another battle -- this one over immigration law.

A new study finds roughly 48,000 same-sex couples in the U.S. include at least one immigrant partner who is not a citizen. And even if those couples have married in states where it's legal, the federal government denies them the same visa rights given to heterosexual spouses.

Host Stephanie Martin talks with Matt Strieker, deputy director of the Williams Institute, the UCLA think tank which produced the study.