Recent genetic research (most of it only published literally in the last two years) has finally begun to contradict the traditional view that this is entirely in the mind with no physical causes.
Here are two different articles one dealing with work done on FtM and the other on MtF (which incidentally appears, in part, to be a rather specialised form of androgen insensitivity. Interesting to me because I was late diagnosed with a partial form of the more general condition.)
http://www.telegraph.co.uk/health/2471724/Gene-variant-may-make-people-transsexual.htmlhttp://www.telegraph.co.uk/health/3265125/Gene-could-hold-key-to-why-transsexual-men-feel-female.htmlIt is however rather important to bear in mind that a genetic trait like this represents a "predisposition" towards something and not a raging certainty. So there is still a nurture aspect involved although from this research it is certainly not, as previously believed, the entire story.
But to answer your question - yes I have several others in my family, in particular one in my grandparents generation who, as far as I can discover was a ->-bleeped-<- (probably repressed TS as he eventually commited suicide). Of course if you were born prior to 1900 there really wasn't any medical help available so the poor soul probably had no other options.
Sadly, as yet this recent research evidence hasn't fully reached the thinking of likes of those compiling the DSM which probably means that for another ten years the fiction that this is all psychological will be allowed to continue unchallenged.
In my opinion, as I have said many times, being Trans in any form, is not a disorder (and hence does not belong in DSM). It is simply a varient state of being which sometimes requires medical intervention when it is causing distress.