Body mass index (BMI, a ratio of body weight to body height) has historically been used by the Services as a screen for enlistment. In fact, each Service has its own criteria for determining acceptable levels of BMI and percentage of body fat. According to the Centers for Disease Prevention and Control (CDC), a BMI over 25 is considered overweight and carries health risks; a BMI over 30 is defined as obese. In the youth population, the prevalence of overweight in children and adolescents tripled between 1963 and 1999 from approximately 5 to 15 percent. The highest prevalence of overweight or risk for overweight during that period was among Mexican American boys and non-Hispanic black girls. Data from the National Health and Nutrition Examination Survey 1999-2000 showing the distribution of BMI for the general population of people ages 16 to 24 indicate that 40 percent have BMIs over 25, and more than 15 percent have BMIs of 30 and over. Thus, the currently recommended BMI enlistment standard used by DoD and most of the Services of 25 or under for young women could lead to disqualification of 40 percent of them from the pool of eligible recruits, while the currently recommended BMI standard of 27.5 percent for young men could lead to disqualification of approximately 25 percent of them from the pool.

Asthma is one of the most common chronic illnesses in the United States. The rate of those who have ever experienced an asthma episode varies between 38 and 43 per 1,000 people in the population. This same rate is evident in individuals ages 15 to 34, but the rate is higher in those under age 15. The rate for non-Hispanic blacks is slightly higher than non-Hispanic whites and Hispanics. CDC data from 1980 to the mid-1990s indicate that women were more than twice as likely as men to be hospitalized for asthma. Historically, asthma has been among the top 10 medical disqualifying conditions for which waivers are requested from the Services. The current military enlistment standard disqualifies any applicant who has experienced asthma symptoms after the 13th birthday. Using asthma as an exclusionary factor is likely to work against the enlistment of minorities and women, as these groups exhibit the highest prevalence of asthma.

Psychological adaptation to military service is critical for successful completion of a tour of duty. Stressors associated with transition from