I worked for IBM in the late 90s and I got the impression they had a very tolerant attitude. Of course, that could change with the manager, etc. A few years ago, I started with one company, where the interviews were done over the phone, to minimize bias. I never met anyone with the company in person, until I showed up to work. I'm about to start a new position with a company that has a very inclusive policy. I also worked at one company, many years ago, where one of the employees was MTF and went through the transition while remaining with the company. Incidentally, I had applied with one company recently, where I knew the person doing the hiring was a trans female. I had met her personally, on a few occasions.