The thing is, being an effeminate guy is (or should be) no different, in terms of gender identification, than a girl being a tomboy. She doesn't see herself as any less a woman because she pursues (typically) masculine endeavours than an effeminate guy would see himself a man. I would hope that a lot of therapists have the common sense to see that.
Heck, if the world worked like that then we might as well tell all the women in soccer, rugby, vehicle maintenance, and bodybuilding to go away and take up flower arranging, social networking, volleyball, hockey and high fashion... and then tell all the guys doing those things to move their butts and replace them... because nether is 'supposed' to be able to do what they're doing.

Of course doing that would just be silly.
I think that the overriding concern should be how you
feel in terms of familiarity, comfort and security, within the confines of your own body rather than what you choose to
do with the one you have. If you identify as male, and that is who your self-image is when you look inside yourself... then you're male. Simple as that. Likewise if you identify as female, and that is what every fiber of your being tells you, then you're female. There's very little debate on the matter.
Very few men and women fit the stereotype of what 'real men' or 'real women' are supposed to be. Both are, in my opinion, social constructs composed of idealised notions and assumptions that have very little basis in reality. Ask a hundred people what constitutes a man and a woman, I bet you'd get close to a hundred different answers.
More likely, I believe, is that all men and women are 'real' men and women, because there's no alternative but to be just that. You can live a lie for so long, but eventually it is shown to be just that, and the 'real' you is the only thing you can be.
The truth lies within each individual as to who they are.

I would think that a therapist would have the insight to see that. And if not, they shouldn't be doing the job.