Simple Answer: I would say don't overthink it, being abused does not define your identity in any way. Don't let people performing lazy psychology get to you, this used to be the top thing the same people would claim with gay and lesbian individuals until it became readily apparent to everyone it was nonsense(and politically incorrect). (Growing up the child of a psychiatrist and now working IT with them, I've heard so many horror stories about supposed experts doing crap like this, you have no idea.)
Long Answer: From what I've found, there seems to be a positive (statistical positive, not beneficial positive of course) correlation between abuse and being trans, that is true, however the data is not often put into context and the "chicken or egg" discussion is quite prevalent.
I could make several arguments that go against the notion that being abused causes being transgender. First and foremost, being transgender has a far clearer statistical causal effect to being abused. This is evident in the number of hate crimes, parents disowning children, and so forth. That alone could account for the entirety of the correlation between being transgender and being abused. Second, the rate of abuse of children is far, far higher than the rate of being transgender. If it was a more direct causal effect, you'd probably see far more people who are transgender as a result. Third, there is no indication that anything remotely approaching a majority of transgender individuals were abused as children, despite potential abuse later in life (as a teenager or older, after the trans identity has been formed, as per the trans causal correlation to abuse above). This proves that, quite definitively, being transgender is a state that can exist independent of abuse, and therefore there is absolutely no reason to assume a causal effect for those who were abused as children. Lastly, it is entirely impossible to guess the reason for much abuse, and in many cases it may very well be that the child showed transgender tendencies early on, prior to recognizing their own status (as of course, it is disturbingly common, or at least was in recent history, for fathers to try to make their sons act more masculine through the thread of violence).
Any mental health professional who insinuates being transgender was caused by abuse needs to head back to school and take an Introductory Stats course and learn the difference between correlation and causation. They also need to look at the studies and notice the little n= number that often show a whopping sample size of a whole 72 people or some such, and then don't even bother specifying cohorts or provide details such as age of abuse. Those are completely unreliable samples that can in no way be indicative of causation, and even simply from a correlation standpoint are at any remotely decent confidence level wind up with margins of error greater than 10%, and are effectively worthless.
(It also comes into issue with the single most common flaw with measuring the transgender population in anything, as we by and large prefer to stay invisible, and the visible trans population is in all likelihood quite different than the invisible population, creating a pool of candidates that share more in common with samples of convenience than they do a proper sample group.)
Sorry, nerded out there a bit, but bottom line is those studies are stupid, and don't question yourself over someone using bad science as a basis to ask amateur hour questions in therapy or during a medical appointment.