Iceland's law stands out in a key way: Companies and organizations with at least 25 full-time employees must actually obtain government certification proving their pay policies are based on factors such as education, skills and performance, not gender. If not, they risk a fine of around $500 each day they are out of compliance.
The demands made by America's laws aren't as rigorous, and that may be in part because the people making, enforcing and implementing the laws are still largely men, suggests Jill Gonzalez, an analyst at financial website WalletHub. "The pay gap still persists because women continue to have disproportionate representation in both corporate leadership positions, as well as political ones," she tells CNBC Make It.
The Center for American Women and Politics reports that women make up less than 20 percent of the U.S. Congress. At the same time, Reuters notes, nearly 50 percent of Iceland's parliament, where the first-of-its-kind pay law was approved, is made up of women.
The Equal Pay Act, first passed by Congress in 1963, mandated that men and women be given equal pay for equal work, and, some states, like Minnesota, have equal-salary policies. But legislation in America has not been very effective: Women, on average, are still paid 20 percent less than men.