Yet homosexuality carries with it profound behavioral implications. Sexual attraction among members of the same sex — living, exercising, fighting and training alongside one another in the closest of quarters — could devastate morale, foster heightened interpersonal tension and lead to division among those who, more than virtually any other group in society, need to act as one.

Male and female military troops barrack separately for an obvious reason — sexual behavior would be inevitable and destructive to unit cohesion and effectiveness.

Would the president compel the armed forces to build single-unit barracks for gay men and women? The logistics of allowing open homosexuality in the military could be unmanageable.

In addition, the medical implications of Obama’s proposal are compelling. According to data released last year by the Centers for Disease Control and Prevention, gay and bisexual men are 50 times more likely to have HIV than heterosexual men.