Specifically for a young person or teenager.

Always use "transgender women" or "transgender youth."

The standard and most respectful term for a person assigned male at birth who identifies as a woman.

If you are looking for a more formal, respectful, or "proper" way to describe this identity, here are better alternatives depending on the context: More Respectful/Formal Terms

The specific Thai term for this identity. While it is the origin of "ladyboy," using the native word is often seen as more culturally aware, though it should still be used with respect.

If the individual does not identify strictly as a woman. Contextual Usage

It is best to follow the lead of how an individual refers to themselves. Many people in the Western LGBTQ+ community find "ladyboy" to be a slur or an outdated trope from the sex industry.