There is evidence of transgender people going back at least 70,000 years. They have been seen in all cultures around the globe. Though how they are treated does vary considerably by culture, it isn't a cultural phenomenon. 

Evidence shows it is biological in nature.  

It has only been in the last 100 years or so that we have had medicines available to do anything to help them. There are differences between the brains of men and women. A woman whose brain is bathed in testosterone is going to have a lot of problems. This is what happens to trans women. These problems are corrected with hormone therapy.

So how is SHE living differently? Different hormones, which cause all sorts of psychological changes. And life: depending on culture, women tend to have different expectations, are treated differently, and more. The differences between men and women are subtle compared to the big similarities, but they do exist. And the consequences of having the wrong hormones are extremely damaging.