romance_target_gender_effect

romance_target_gender_effect = {
	hidden_effect = {
		if = {
			limit = { NOT = { has_sexuality = asexual } }
			random_list = {
				50 = {
					trigger = { is_attracted_to_women = yes }
					dummy_female = { save_scope_as = $SCOPE_NAME$ }
				}
				50 = {
					trigger = { is_attracted_to_men = yes }
					dummy_male = { save_scope_as = $SCOPE_NAME$ }
				}
			}
		}
		else = {	
			#If this effect is used for content not blocked for asexual characters, we assume this effect is used to find out what gender society expects us to prefer.
			save_temporary_scope_as = asexual_char

			#If homosexuality seems to be accepted, there is a change of same gender attraction target
			if = {
				limit = {
					NOR = {
						trait_is_shunned_or_criminal_in_rite_trigger = {
							RITE = scope:asexual_char.rite
							TRAIT = trait:sodomite
							GENDER_CHARACTER = dummy_female
						}
						trait_is_shunned_or_criminal_in_rite_trigger = {
							RITE = scope:asexual_char.rite
							TRAIT = trait:sodomite
							GENDER_CHARACTER = dummy_male
						}
					}
				}
				random_list = {
					10 = {
						modifier = {
							is_female = yes
							add = 80
						}
						dummy_male = { save_scope_as = $SCOPE_NAME$ }
					}
					10 = {
						modifier = {
							is_male = yes
							add = 80
						}
						dummy_female = { save_scope_as = $SCOPE_NAME$ }
					}
				}
			}
			#If homosexuality isn't accepted, we 100% go with opposite sex
			else = {
				if = {
					limit = { is_female = yes }
					dummy_male = { save_scope_as = $SCOPE_NAME$ }
				}
				else = {
					dummy_female = { save_scope_as = $SCOPE_NAME$ }
				}
			}
		}
	}
}

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