i wouldn't go with Tr for either a boy or a girl...one of my friends names is Jennifer...her brother is Jason and her sister is Jessica (i think but not sure...it's definetly another 'J') and she doesn't like the fact that everyone's name starts with a 'J'

a name with an R would be nice cuz then you'll have R, S, T - youngest to oldest which is cool in itself - of course not many people would look at it that way