child_sexuality_distribution_effect

child_sexuality_distribution_effect = {
	every_ruler = {
		if = {
			limit = {
				is_adult = no
				age >= 10
			}
			game_rule_sexuality_distribution_reroll_effect = yes
		}

		every_courtier_or_guest = {
			if = {
				limit = {
					is_adult = no
					age >= 10
				}
				game_rule_sexuality_distribution_reroll_effect = yes
			}
		}

		every_held_title = {
			title_tier = county
			title_province = { save_scope_as = pool_province }
			every_pool_character = {
				limit = { NOT = { is_in_list = pool_characters } }
				province = scope:pool_province
				add_to_list = pool_characters
			}
		}
	}

	every_in_list = {
		list = pool_characters
		if = {
			limit = {
				is_adult = no
				age >= 10
			}
			game_rule_sexuality_distribution_reroll_effect = yes
		}
	}
}

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