historical_pregnancy_effect

historical_pregnancy_effect = {
	if = {
		limit = { exists = var:historical_pregnancy }
		switch = {
			trigger = var:historical_pregnancy
			flag:antoku = {
				save_scope_as = mother
				character:japanese_yamato_54 = { save_scope_as = father }
				create_character = {
					name = "Tokihito" # birth name of Antoku
					gender_female_chance = 0
					random_traits = no
					age = 0
					dynasty_house = scope:father.house # Yamato
					employer = scope:mother.employer
					father = scope:father # Emperor Takakura
					mother = scope:mother # Noriko
					faith = scope:father.faith
					rite = scope:father.rite
					culture = scope:father.culture
					save_scope_as = child
				}
				scope:child = { add_pressed_claim = title:k_chrysanthemum_throne }
			}
		}
		create_character_memory = {
			type = child_born
			participants = { child = scope:child }
		}
		current_travel_plan ?= { 
			if = {
				limit = {
					travel_plan_owner = { is_ruler = yes }
				}
				add_companion = scope:child
			}
		}
	}
}

As written in game/common/scripted_effects/00_pregnancy_effects.txt.