For decades, soccer officials in the United States simply wanted some fans in their stadiums. Now they have them, and some of those fans have brought an unexpected problem: a vulgar chant, in the vein of more notoriously rabid soccer fans in other countries.

Hardly clever, it is only three words — an insult directed at the opposing goalkeeper — but enough to give M.L.S. officials fits as they hear it spill over into live television broadcasts. The chant’s simplicity is what makes it appealing or appalling, depending on your perspective.

It has been heard this season at Major League Soccer games in Seattle; Sandy, Utah; Harrison, N.J.; Kansas City, Kan.; and Columbus, Ohio, among other places. It has been shouted by thousands of fans at men’s national team games, too.

“Sport is spontaneous, it’s passionate, and I don’t think any of us would want to remove that from the game,” said Evan Dabby, senior director of supporter relations at M.L.S. “That’s what makes it beautiful. That’s what makes it enticing.”