I have a recommendation for clarity: Do you mean to say you want your anthro characters to be flat-chested? Currently, there's a little bit of confusion there-- I recommend a comma after "female or not", otherwise that "not" bleeds right into the next statement. People with poor reading comprehension would probably read it as "please not have them be flat chested."
Otherwise a rewording would be super ideal: Please if you make me an anthro character have them be flat chested, female or not!!! Thank you!