For the Children is related to the seasonal world event Children's Week. If you complete this achievement you will be rewarded with the title <Matron> or <Patron> depending on your character's gender. This achievement is also a criterion of the meta-achievement What A Long, Strange Trip It's Been.
If your character's gender changes while showing the <Matron> or <Patron> title, your title will also change. This frequently happens to characters traveling around Icecrown or using morphs such as an [Iron Boot Flask].
The gender (and title) change also specifically happens to male characters entering Brunnhildar Village[48.2, 69.2]
, where the Hyldnir are all female, and to female characters entering Netherwing Ledge[70, 85]
where the Dragonmawfel orcs are all male. On leaving these areas, your character's gender (and therefore, <Matron> or <Patron> title) will both revert to normal.