diff --git a/include/constants/pokemon_config.h b/include/constants/pokemon_config.h
index 739d62c5e1..685f5df42d 100644
--- a/include/constants/pokemon_config.h
+++ b/include/constants/pokemon_config.h
@@ -12,13 +12,14 @@
 #define GEN_8 5
 #endif
 
-#define P_UPDATED_TYPES         GEN_8 // In Gen6+, several Pokémon were changed to be partially or fully Fairy type.
+#define P_UPDATED_TYPES         GEN_8 // Since Gen 6, several Pokémon were changed to be partially or fully Fairy type.
 #define P_UPDATED_STATS         GEN_8 // Since Gen 6, Pokémon stats are updated with each passing generation.
 #define P_UPDATED_ABILITIES     GEN_8 // Since Gen 6, certain Pokémon have their abilities changed. Requires BATTLE_ENGINE for Gen4+ abilities.
 #define P_UPDATED_EGG_GROUPS    GEN_8 // Since Gen 8, certain Pokémon have gained new egg groups.
 #define P_SHEDINJA_BALL         GEN_8 // Since Gen 4, Shedinja requires a Poké Ball for its evolution. In Gen 3, Shedinja inherits Nincada's Ball.
 #define P_LEGENDARY_PERFECT_IVS GEN_8 // Since Gen 6, Legendaries, Mythicals and Ultra Beasts found in the wild or given through gifts have at least 3 perfect IVs.
 #define P_KADABRA_EVERSTONE     GEN_8 // Since Gen 4, Kadabra can evolve even when holding an Everstone.
+#define P_NIDORAN_M_DITTO_BREED GEN_8 // Since Gen 5, when Nidoran♂ breeds with Ditto it can produce Nidoran♀ offspring. Before, it would only yield male offspring. This change also applies to Volbeat.
 
 #define P_ENABLE_DEBUG          TRUE  // Enables a debug menu for pokemon sprites and icons, accessed by pressing SELECT in the summary screen.
 
diff --git a/src/daycare.c b/src/daycare.c
index 7c4bd609f6..01ecee950d 100644
--- a/src/daycare.c
+++ b/src/daycare.c
@@ -793,13 +793,25 @@ static u16 DetermineEggSpeciesAndParentSlots(struct DayCare *daycare, u8 *parent
 
     eggSpecies = GetEggSpecies(species[parentSlots[0]]);
     if (eggSpecies == SPECIES_NIDORAN_F && daycare->offspringPersonality & EGG_GENDER_MALE)
-    {
         eggSpecies = SPECIES_NIDORAN_M;
-    }
-    if (eggSpecies == SPECIES_ILLUMISE && daycare->offspringPersonality & EGG_GENDER_MALE)
-    {
+    else if (eggSpecies == SPECIES_ILLUMISE && daycare->offspringPersonality & EGG_GENDER_MALE)
         eggSpecies = SPECIES_VOLBEAT;
-    }
+    #if P_NIDORAN_M_DITTO_BREED >= GEN_5
+        else if (eggSpecies == SPECIES_NIDORAN_M && !(daycare->offspringPersonality & EGG_GENDER_MALE))
+            eggSpecies = SPECIES_NIDORAN_F;
+        else if (eggSpecies == SPECIES_VOLBEAT && !(daycare->offspringPersonality & EGG_GENDER_MALE))
+            eggSpecies = SPECIES_ILLUMISE;
+    #endif
+    else if (eggSpecies == SPECIES_MANAPHY)
+        eggSpecies = SPECIES_PHIONE;
+    else if (eggSpecies == SPECIES_SINISTEA_ANTIQUE)
+        eggSpecies = SPECIES_SINISTEA;
+    else if (GET_BASE_SPECIES_ID(eggSpecies) == SPECIES_VIVILLON)
+        eggSpecies = SPECIES_SCATTERBUG;
+    else if (GET_BASE_SPECIES_ID(eggSpecies) == SPECIES_ROTOM)
+        eggSpecies = SPECIES_ROTOM;
+    else if (GET_BASE_SPECIES_ID(eggSpecies) == SPECIES_FURFROU)
+        eggSpecies = SPECIES_FURFROU;
 
     // Make Ditto the "mother" slot if the other daycare mon is male.
     if (species[parentSlots[1]] == SPECIES_DITTO && GetBoxMonGender(&daycare->mons[parentSlots[0]].mon) != MON_FEMALE)