Hi Wild Rose,
The medical conditions you can pin the blame on are rather serious - congestive heart failure, or prostate/testicular cancer. You could use these as excuses at work I suppose - treatment for prostate cancer could be handled on an outpatient basis, I reckon. And it's something very personal - is someone at work really going to pump you for information here?
There was a big thread on
low dose HRT and some of the posters brought up how to cover up feminization - growing beards, wearing dark/loose shirts and minimizing bras, etc. Like you they need or prefer to present as male at work.
