Here is the full list of all 46 Conception PLUS: Maidens of the Twelve Stars achievements.
Obtain all achievements.
Give birth to 200 Star Children.
Use all Team Colors.
Have 100 Star Children go independent.
Complete Harem ending.
Complete Collette's ending.
Complete Farun's ending.
Complete Sue's ending.
Complete Reone's ending.
Complete Mirei's ending.
Complete Mahiru's ending.
Complete Femiruna's ending.
Complete Ruka's ending.
Complete Lillith's ending.
Complete Tarua's ending.
Complete Arie's ending.
Complete Yuzuha's ending.
Complete Alfie's ending.
Complete a total of 100 Chain Combos.
Give birth to a Star Child of each class.
Clear 12 Constellation Labyrinths.
Give birth to the special class "Bondsman."
Give birth to the special class "Ninja."
Give birth to the special class "Dungeon Master."
Clear 6 Constellation Labyrinths.
Complete all quests.
Obtain all armor.
Obtain all accessories.
Obtain all weapons.
Complete main scenario.
Complete Normal ending.
Clear 4 Constellation Labyrinths.
Give birth to the special class "Sage."
Perform the Tri-Mating ritual.
Clear 3 Constellation Labyrinths.
MECUNITE a total of 10 times.
Have 25 Star Children go independent.
Clear 2 Constellation Labyrinths.
Clear 1 Constellation Labyrinth.
Visited the Map Point "Gift Shop."
Complete a total of 8 Chain Combos.
Insta-kill 100 Impurities.
Give birth to 12 Star Children.
Visited the Map Point "Scavenger."
Visited the Map Point "Day Camp."
Give birth to your first Star Child.