They weren't gay  (homosexual) priests? 
A.) Homosexual/Gay - sexual orientation/attraction to persons of the same gender/sex
B.) Boys - Non-Adult Males (for a brief certitude in definition.)
C.) Male priests - Men who are priests
D.) Gay priests engage in sex acts with boys
So, if priests are A and C, and employ that orientation with B, then they are D. If my logic is wrong, can you show/prove?