Coming out as transgender in the mathematical community I don't know if MO is the right place to ask such a question, but anyway it's my only hope to get an answer, and it's very important for me (not to say 'vital'); so let's try.
I'm at this time a Ph.D. student, and I plan to defend in the spring of 2018. I'm currently looking for a postdoc position for next year. I am, at this time, known as a man in the mathematical community, but I'm actually a trans woman, beginning my gender transition. I have two problems. Firstly, I will have to come out as transgender, in at most a few years, in the mathematical community, and I'm quite fearful about the consequences (for example, for my career). Secondly, I have to ensure before applying for a postdoc that in the country where I apply, I will be able to pursue my transition, I will be accepted as I am at the university, and that there won't be any major threat to my security (because of the policy of the country regarding trans people, for instance). For this reason, having contacts in these countries who are reaserchers in maths and are familiar with transidentity questions would be very helpful for me, as I have no other means to get the info I need.
So my first question is: are there, here, trans mathematicians who would be willing to talk with me, in private, about how they came out (if they had to) in the mathematical community, how it was accepted, what has been the consequences for their career, and more generally what was their experience as trans mathematicians? (I also have other specific questions like, for instance, how to deal with a change of your first name when you already have published under your former name?) Even if you're not trans, if you have information about all of this (if you know a trans mathematician for example), I would be interested.
My second question is: in the countries where I am interested in applying for a postdoc, that is Spain, the Czech Republic, Canada, the US, and Brazil, do you have any contacts, in the academic world, who are familiar with LGBT questions, and who could give me an idea about the situation of trans people in their country, and especially at the university? (In order for me to know if it's safe to apply there or not?)
If some of you are yourselves why I don't ask these questions directly to researchers of the universities where I want to apply: that's simply because it's not safe. Trans people have to face a lot of discrimination and you never know if speaking about your transidentity with someone you don't know is safe or not - that's the reason why I choosed to ask it anonymously here, first.
(You can contact me in private at rdm.v[at]yahoo[dot]com.)
 A: Spectra is an organization for LGBT mathematicians. I hope that you can find people to safely discuss your questions with there.
A: If you will be at the Joint Math Meetings in San Diego, there will be a Spectra-sponsored MAA panel on Out in Mathematics: Professional Issues Facing LGBTQ Mathematicians, Thursday, January 11th, 1pm - 2:20pm, Room 1A, Upper Level, San Diego Convention Center. It will be moderated by Lily Khadjavi (Loyola Marymount University), with panelists Shelly Bouchat (Indiana University of Pennsylvania), Juliette Bruce (University of Wisconsin Madison), Ron Buckmire (NSF), Frank Farris (Santa Clara University), and Emily Riehl (Johns Hopkins University). 
Spectra is hosting an informal reception later that day, Thursday, January 11th, 2018, 6pm-8pm, Catalina Room, Marriott Marquis, which is a great way to meet people. This event has been held at every JMM since 1995. Here is the story of how it started, and shows how our professional societies took a courageous stand even during the anti-gay political storms of in the 1990s. It continues to have relevance today.
In November, 1992, Colorado residents passed an amendment to their Constitution targeting three local anti-discrimination ordinances, nullifying them and making any further attempts unconstitutional. The 1995 Joint Math Meetings were scheduled for Denver. Two mathematicians wrote to the AMS and MAA boards in late 1992 requesting that the JMM be moved, citing the blatant anti-gay animus of the amendment (so blatant that in 1995 the US Supreme Court ruled it unconstitutional). The boards met in a joint session at the 1993 JMM and passed a resolution recommending this move, arguing that the societies have a duty to protect participants from possible discrimination. Shortly afterwards, the Joint Meetings Committee moved the 1995 JMM to San Francisco. The Denver cancellation resulted in a lawsuit from the conference hotels, ultimately settled for $35,000, split evenly between the AMS and MAA. Increased attendance at the San Francisco meeting likely covered most of this cost.
Despite short notice and communication difficulties (this was pre-Facebook!), an informal event at the San Francisco JMM held at a restaurant near the conference hotel drew nearly 100 people. A group of concerned mathematicians felt it would be very useful to have a more visible presence at future JMMs, and formed a steering committee, together with setting up an email group. This group eventually was formalized as Spectra. 
Spectra is holding a brainstorming session on Friday, January 12th, 2018, 3pm-5pm, Torrey Pines 2, Marriott Marquis and everyone is welcome to attend and contribute ideas.
