This is something I've never thought of, but I would not go down that route. I recently discovered a love of wearing bras (though have not found the perfect bra for me yet), and while I would want maybe a size bigger, I would not want to go down a permanent route with implants.

I guess the bottom line is that why should the gender/identification of the individual have any impact on whether the person has implants? Take a long think, make an informed choice, but realise this is not something you can quickly or cheaply reverse.