 Some 97 percent of male BYU graduates and 32 percent of female graduates took a hiatus from their undergraduate studies at one point to serve as LDS missionaries . In October 2012 , the LDS Church announced at its general conference that young men could serve a mission after they turn 18 and have graduated from high school , rather than after age 19 under the old policy . Many young men would often attend a semester or two of higher education prior to beginning missionary service . This policy change will likely impact what has been the traditional incoming freshman class at BYU . Female students may now begin their missionary service anytime after turning 19 , rather than age 21 under the previous policy . For males , a full @-@ time mission is two years in length , and for females it lasts 18 months . 
