Given that Walmart is the country’s largest private employer it’s not terribly surprising that the U.S. Supreme Court has decided to have a look at the sex discrimination lawsuit filed against the retailer — the largest class-action suit of its kind in U.S. history.

The lawsuit began as a claim by a small group of female Walmart staffers. It was granted class-action status in April by a California appeals court, expanding the potential plaintiff base to upward of 1.5 million current and former female Walmart employees.

Walmart will be arguing before the Supremes that the claims by the various plaintiffs are too diverse to proceed as a unified class-action.

“The current confusion in class-action law is harmful for everyone — employers, employees, businesses of all types and sizes and the civil justice system. These are exceedingly important issues that reach far beyond this particular case,” reads a statement from the retail giant.

Walmart pointed out in its appeal to the Supreme Court that the potential plaintiff base for this case “is larger than the active-duty personnel in the Army, Navy, Air Force, Marines and Coast Guard combined.”

On the flip side, lawyers for the original plaintiffs in the case says that the retail chain is painting itself as an entity that “is too big to be held accountable… The class is large because Wal-Mart is the nation’s largest employer and manages its operations and employment practices in a highly uniform and centralized manner.”

The arguments won’t likely be heard until March and a ruling is expected on the matter in June. The court will not be deciding on the merits of the gender discrimination claims, but on whether or not the lawsuit warrants its class-action certification.

Wal-Mart class-action appeal goes to Supreme Court [Reuters]