According to the NND Dictionary here, I know it says "people who are able to sing both genders." But I'm constantly finding utaite here would I would consider as ryouseirui, aren't labelled as such so I can't help feeling confused.
For example, are male utaite who constantly sing in a high or feminine manner like Mafumafu or gender is unknown (but most likely female) like MidoriInu. not considered ryouseirui?