Angel

From Galaxy Angel Wiki, the comprehensive Project G.A. reference.

An Angel (エンジェル) was a person who was a member of either the Moon or Rune Angel Troupe. Up until TCY 417, Angels were required to have an extremely rare inborn ability to manipulate the H.A.L.O. System, due to that being the only way to control Emblem Frames at that time. For an unknown reason, only women were found to possess this ability. By the end of TCY 417, only 12 women had been found with this ability.

In late TCY 416 however, Brave Heart was discovered, and though not an Emblem Frame, was soon found to have an important function in supporting the NEUE Emblem Frames, and made part of the Rune Angel Troupe. Since it was not an Emblem Frame, anyone could pilot it. As such, early the next year, Kazuya Shiranami was selected to be its pilot, and became the first male Angel. Later, the advent of the mass production Emblem Frames, which utilized an AI system instead of the H.A.L.O. System, allowed for more male members.