It appears that there is, indeed, an uptick in vasectomies in the U.S. during March. A 2018 study of vasectomy trends in the U.S. found that most vasectomies are performed in March, as well as during the end-of-year holidays.

But rather than an organic trend, the uptick in March may have been spurred by media headlines and marketing, experts told Live Science.

It’s “an urban legend that led to fact,” said Dr. Ajay Nangia, a professor and vice chair of urology at The University of Kansas Health System.

According to Nangia, the origins of the idea trace back to around 2004, when a urologist tried to promote vasectomies during March Madness. News outlets picked up on the idea, which eventually led to more men actually booking vasectomies in March. “It’s become self-perpetuating,” Nangia told Live Science.