I totally agree that it is very likely that trans will one day be shown to be "in the brain." I know tons of LGBT people (and am queer myself), & with most of them it was evident since childhood. There is already some proof of a "gay gene," for example.
That said, I'm DEEPLY concerned about people trying to change the definition of intersex to say that trans is a "type of intersex condition." For ethical reasons & out of respect to trans people, I would never, as a non-trans person, seek to change the definition of trans -- especially w/o consulting trans people or against their will. Even more importantly, if our definition is changed , intersex people, particularly infants & children, will suffer even more than we already do. Intersex infants are operated on w/o their consent every hour b/c of physical differences that are visible. Even in the cases where the differences are not evident at birth b/c they are chromosomal, for example, we are STILL discriminated against, tortured, &/or stripped of our rights if/when this difference is discovered. This is evidenced by all the Olympic intersex athletes who were stripped of medals & denied the right to compete when a simple swab of the mouth for a chromosome test revealed that they were intersex (some of them ended up committing suicide as a result.) After these chromosome tests stopped, there have still been cases like that of Caster Semenya, who was accused of not being a woman & denied the right to compete during her "gender verification testing." She has not publicly revealed whether or not she is intersex, but one can assume that she is b/c it would have quickly been revealed with all the medical tests she was forced to undergo if she had been a non-intersex male or female. It seems she did not even know she was intersex herself but was publicly outed at the age of only 18 & was on suicide watch as a result. Even now that she has been allowed to compete, the rumor is that she was forced to take estrogen -- which she had never wanted to do -- in order to do so. As a result of my activism I was invited to be a expert panelist at the International Olympic Committee meeting on the topic of intersex women in competition. One of the arguments they tried to make is that there is already a structure in place for trans athletes to compete --where they have to medically demonstrate that they have transitioned enough to compete as their chosen sex -- so intersex people can just use the same one. They were trying to conflate intersex with trans to make it easier for them to deal with us despite the huge difference that trans athletes CHOSE to make whatever changes they made to their body -- they are not being forced into changing their body by athletic committees.
These are just a few examples which show the very real dangers & discrimination that intersex people are subjected to b/c our differences can be physically shown. Trans people are not vulnerable to these types of abuses because something "in the brain" cannot be revealed with medical tests.
Intersex people are struggling to get the right to do what we want, if anything, to our bodies--- a right which trans people already have, as everyone should -- & to attain the legal rights & protections that trans people already have in may countries. I do not think this is your objective, but you should understand that trying to change our definition directly works against intersex people & our struggle for human rights & autonomy over our bodies. It confuses people, most of which are already confused about what intersex is anyway. To this day, the majority of intersex people are not even out b/c it is such a personal thing to reveal (often pertaining to atypical genitals or sex organs), b/c our culture is SO attached to this idea of only "male" or "female" existing that it is psychologically difficult (as well as sometimes dangerous) to come out as something other than that, &/or because they are so traumatized by all the nonconsensual medical "normalizing treatments" they received as children.
As I said earlier, being gay/lesbian can also be said to be "in the brain." However, gays & lesbians are not trying to say they are intersex or change the definition of intersex to include them. Many have even argued, rightfully so, that although the "gay gene" theory is interesting, gays/lesbians shouldn't have to "prove" that it's something they're born with in order to not be discriminated against.
It is very easy for trans people to simply say that trans is something in the brain that one is born with, just as some gay people do. There is no reason to appropriate the intersex label/definition to do this.
Simply put, intersex people are not even "on the map" yet when it comes to people understanding what we are. Confusing people about what we are now, before we have even established ourselves within society, just makes it easier to make us surgically disappear. This is evidenced by a recent medical article by the American Assoc of Endocrinologists & Gynecologists that called intersex a subcategory of trans. They know better than most that we are not, but if they do this, call us trans, it makes their abuses easier to get away with b/c instead of having to admit that it is wrong to operate on someone's genitals against their will, if an intersex child grows up & says they don't like what was done to them or don't feel they are the sex they were surgically assigned to be, well then the medical establishment can just say, "oh, we didn't do anything wrong, you're just trans." And again, intersex gets disappeared.
Please do not facilitate the abuses against intersex people. Let intersex be intersex as we let trans be trans. We are comrades in the struggle against gender-variant phobia and should respect each other's needs as such. Thank you.
Hida Viloria, Chairperson, Organisation Intersex International