It's a hectic morning at the home of Kathleen O'Donnell and her wife, Casey. Kathleen is getting their four-year-old foster daughter ready for the park. She got placed with them overnight. Casey is wrangling the four dogs. They've already got their 11-year-old son off to school.

They live on a tree-lined street in Billings, Montana. It's a place they've called home since 2014.

"All of my family lives in Billings, so with a kid we wanted to be near them," Kathleen said.

But when the same-sex couple made the move, they knew it came with risks. While five Montana cities have local non-discrimination ordinances on the basis of sexual orientation and gender identity, Billings, the state's largest city, is not one of them.

Nor does the state have an explicit law that protects LGBTQ people from discrimination in housing, employment or public accommodations. Neither do more than half of U.S. states, leaving millions to rely on a patchwork of protections that vary depending on where they happen to live.

It's why Kathleen and her wife are closely watching three upcoming cases that will be argued in front of the Supreme Court on Tuesday related to Title VII, the federal statute that makes it illegal to discriminate against someone at work on the basis of sex. The court is hearing arguments on whether the definition of sex in Title VII includes sexual orientation and gender identity.

"What these cases will decide is does the federal statute that prohibits sex discrimination in employment, cover discrimination on the basis of someone's sexual orientation or their gender identity, because those forms of discrimination are sex-based," said Adam Romero, the federal policy director at the Williams Institute at the UCLA School of Law.

Whatever the court decides, Romero said, will have a ripple effect well beyond employment. Read more and listen to the story via NPR