University of Michigan surgeon Dr. Lazar Greenfield, 78, resigned Sunday after his Valentine's Day editorial in the group's monthly newspaper sparked controversy, the Detroit Free Press reported.
In the editorial, Greenfield discussed the virtues of semen as a mood-enhancer for women.
Referring to controversial research, Greenfield wrote "there's a deeper bond between men and women than St. Valentine would have suspected, and now we know there's a better gift for that day than chocolates."
The ACS issued a statement about Greenfield's resignation.
"At this critical juncture for surgery and healthcare in America, it is important that the American College of Surgeons not be distracted by any issues that would diminish its focus on improving care of the surgical patient," Dr. Carlos Pellegrini, chairman of the group's Board of Regents, said in the statement.