answered:
Oh man, I pity you for having such a shitty English teacher. Only verbs can be transformed into participles by adding “-ed” to the end of the word, and transgender is an adjective, not a verb.
Transgender should be used as an adjective, not as a noun or verb. Do not say, ‘Judah is a transgender,’ or ‘The parade included many transgenders.’ Instead say, ‘Judah is a transgender person,’ or ‘The parade included many transgender people.’
There’s your English lesson for the day.