Good news for all you philanthropic exhibitionists out there—this month brings an opportunity to run around in your underwear for a good cause.

Cupid's Undie Run, a mile-long, underwear-only race, will be held Feb. 9 in 18 cities to raise money for the Children's Tumor Foundation, an organization that works to improve the health and lives of people living with neurofibromatosis.

Known as NF, neurofibromatosis is a genetic disorder that allows tumors to grow on nerves throughout the body and can lead to blindness, deafness, cancer and chronic pain. More than 2 million people worldwide suffer from NF.

The undie run, first held in Washington, D.C., in 2010, was founded by Chad Leathers and three of his friends. Leathers was driven to raise awareness of NF after his younger brother Drew was diagnosed with a rare form of the disease. Since its inception, the undie run has raised more than $400,000 for the Children's Tumor Foundation, which Leathers credits with helping his brother make a “remarkable” recovery.

“Because of the efforts of the Children's Tumor Foundation and the NF research community, he has been given a new lease on life,” Leathers says. “He went from living in a bed, totally paralyzed from the neck down, to standing on a stage as our NF ambassador for the Children's Tumor Foundation this past December.”

This year, the event is on pace for more than 8,000 runners and will have its first participating city outside of the U.S. in Sydney.

To learn more about the run or to register, visit cupidsundierun.com.