I would think a transgender person would be the expert on how gender dysphoria has impacted their life and how the ability to live as their "true" gender has either improved or diminished their life.You don't have to trust what I say is true. Research what I say and form your own educated opinion. I work closely with this population and I have my own insight that a parent or trans person does not have.
However, there is a unique perspective to gain from being transgender or being a parent of a transgender. But just being trans does not make you an expert.