The gay community (with the exception of undercover black males) are very conscious of STD's, moreso than individuals who are heterosexual. Sexual orientation does not hinder your ability to lead or be supportive of the mission. We all have differences when that uniform is off but that does not affect what we do when the uniform is on.

As for the blood thing, if you cannot give blood the military makes it known and again.. does not hinder the mission. I have a G-6PD deficiency which prevents me from giving blood, they just go right on to the next person.